FORM OF SERIES A COMMON SHARE PURCHASE WARRANT AETERNA ZENTARIS INC. Warrant Shares: Issue Date: March , 2015 Warrant Number: W- Initial Exercise Date: March , 2015 THIS SERIES A COMMON SHARE PURCHASE WARRANT (this Warra

FORM OF SERIES A COMMON SHARE PURCHASE WARRANT

AETERNA ZENTARIS INC.

THIS SERIES A COMMON SHARE PURCHASE WARRANT (this Warrant ) certifies that, for value

received, (the Holder ) is entitled, upon the terms and subject to the limitations on exercise and the

conditions hereinafter set forth, at any time on or after March , 2015 (the Initial Exercise Date ) and on or prior to the close of business on the Termination Date (as defined below) but not thereafter, to

subscribe for and purchase from Aeterna Zentaris Inc., a Canadian corporation (the Corporation ), up to Common Shares (as defined

below) (the Warrant Shares ) of the capital of the Corporation. The purchase price of one Common Share under this Warrant shall be equal to the Exercise Price, as defined in Section 1(b) hereof. This Warrant is one of the

Warrants (collectively, the Warrants ) issued by the Corporation in connection with an offering of units pursuant to that certain Underwriting Agreement, dated March , 2015 (the Subscription

Date ), by and between the Corporation and the underwriter(s) named therein. Except as otherwise defined herein, capitalized terms in this Warrant shall have the meanings set forth in Section 5.

Section 1. Exercise.

(a) Exercise of Warrant. Exercise of the purchase rights represented by this Warrant may be made, in whole or in part,

at any time or times on or after the Initial Exercise Date and on or before the Termination Date by delivery to the Corporation (or such other office or agency of the Corporation as it may designate by notice in writing to the registered Holder at

the address of the Holder appearing on the books of the Corporation) of a duly executed copy by facsimile or e-mail of the Notice of Exercise Form annexed hereto. No ink original Notice of Exercise shall be required, nor shall any medallion

guarantee (or other type of guarantee or notarization) of any Notice of Exercise form be required. On or before the first Trading Day following the date on which the Corporation has received the Notice of Exercise Form (the date upon which the

Corporation has received the Notice of Exercise Form, the Exercise Date ), the Corporation shall transmit by facsimile or e-mail transmission an acknowledgment of confirmation of receipt of the Notice of Exercise Form to the Holder

and the Corporation s transfer agent for the Common Shares (the Transfer Agent ). The Corporation shall deliver any objection to the Notice of Exercise Form on or before the end of the first Trading Day following the date on

which the Corporation has received the Notice of Exercise Form. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender this Warrant to the Corporation until the Holder has purchased all of the

Warrant Shares available hereunder and this Warrant has been exercised in full, in which case, the Holder shall surrender this Warrant to the Corporation for cancellation within three (3) Trading Days of the date the final Notice of Exercise

Form is delivered to the Corporation. Partial exercises of this Warrant resulting in purchases of a portion of the total number of Warrant Shares available hereunder shall have the effect of lowering the outstanding number of Warrant Shares

purchasable hereunder in

an amount equal to the applicable number of Warrant Shares purchased. The Holder and the Corporation shall maintain records showing the number of Warrant Shares purchased and the date of such

purchases. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares

available for purchase hereunder at any given time will be less than the amount stated on the face hereof.

Exercise Price. The exercise price per Common Share under this Warrant shall be US$ , subject to adjustment hereunder (the Exercise Price ).

(c) Cashless Exercise.

(i) Notwithstanding anything contained herein to the contrary (other than Section 1(f) below), the Holder may, in its

sole discretion, exercise this Warrant in whole or in part and, in lieu of making the cash payment of the Exercise Price otherwise contemplated to be made to the Corporation upon such exercise, elect instead to receive upon such exercise the

Net Number of Common Shares determined according to the following formula (a Cashless Exercise ):

For purposes of the foregoing formula:

A= the total number of shares with respect to which this Warrant is then being exercised.

B = the quotient of (x) the sum of the VWAP of the Common Shares of each of the five (5) Trading Days ending at the close of business

on NASDAQ or, if NASDAQ is not the principal U.S. trading market for the Common Shares, then on the principal securities exchange or securities market in the U.S. on which the Common Shares are then traded, immediately prior to the time of exercise

as set forth in the applicable Notice of Exercise, divided by (y) five (5).

C = the Exercise Price then in effect for the applicable

Warrant Shares at the time of such exercise.

D = as applicable: (i) the Closing Sale Price of the Common Shares on the Trading Day

immediately preceding the date of the applicable Notice of Exercise if such Notice of Exercise is (1) both executed and delivered pursuant to Section 1(a) hereof on a day that is not a Trading Day or (2) both executed and delivered

pursuant to Section 1(a) hereof on a Trading Day prior to the opening of regular trading hours (as defined in Rule 600(b)(64) of Regulation NMS promulgated under the federal securities laws) on such Trading Day, (ii) the Bid

Price of the Common Shares as of the time of the Holder s execution of the applicable Notice of Exercise if such Notice of Exercise is executed during regular trading hours on a Trading Day and is delivered within two (2) hours

thereafter pursuant to Section 1(a) hereof, or (iii) the

Closing Sale Price of the Common Shares on the date of the applicable Notice of Exercise if the date of such Notice of Exercise is a Trading Day and such Notice of Exercise is both executed and

delivered pursuant to Section 1(a) hereof after the close of regular trading hours on such Trading Day.

(ii) For purposes of Rule 144(d) promulgated under the 1933 Act, as in effect on the date hereof, it is intended that the

Warrant Shares issued in a Cashless Exercise shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued pursuant to the

Underwriting Agreement. If Warrant Shares are issued in a Cashless Exercise, the parties acknowledge and agree that in accordance with Section 3(a)(9) of the 1933 Act, the Warrant Shares shall take on the registered characteristics of the Warrants

being exercised. The Corporation agrees not to take any position contrary to this Section 1(c)(ii).

In the case of a dispute as to the determination of the Exercise Price or the arithmetic calculation of the number of Warrant Shares to be issued pursuant to the terms hereof, the Corporation shall promptly issue to the Holder the number of Warrant

Shares that are not disputed and resolve such dispute in accordance with Section 4(f).

(i) Share Delivery. On or before the end of the first Trading Day following the date on which the

Corporation has received the Notice of Exercise Form and, provided, that, the Holder has paid in full the aggregate Exercise Price for the Warrants being exercised by wire transfer or cashier s check drawn on a United States bank or pursuant to

the Cashless Exercise procedure specified in Section 1(c) above (the Share Delivery Date ), the Corporation shall, (X) provided that the Transfer Agent is participating in The Depository Trust Corporation

( DTC ) Fast Automated Securities Transfer Program (the FAST Program ) and so long as the certificates therefor are not required to bear a legend regarding restriction on transferability (which includes, without

limitation, any exercise of this Warrant pursuant to a Cashless Exercise), upon the request of the Holder, credit such aggregate number of Common Shares to which the Holder is entitled pursuant to such exercise to the Holder s or its

designee s balance account with DTC through its Deposit/Withdrawal at Custodian system, or (Y), if the Transfer Agent is not participating in the FAST Program or if the certificates are required to bear a legend regarding restriction on

transferability, issue and dispatch by overnight courier to the address as specified in the Notice of Exercise Form, a certificate, registered in the Corporation s share register in the name of the Holder or its designee, representing the

number of Common Shares to which the Holder is entitled pursuant to such exercise. The Warrant Shares shall be deemed to have been issued, and the Holder or any other person so designated to be named therein shall be deemed to have become a holder

of record of such shares for all purposes, as of the date this Warrant has been properly exercised, with payment to the Corporation of the Exercise Price (or by Cashless Exercise), irrespective of the date such Warrant Shares are credited to the

Holder s DTC account or the date of delivery of the certificates evidencing such Warrant Shares, as the case may be. The Corporation shall pay any and all taxes and other expenses of the Corporation (including overnight delivery charges) that

may be payable with respect to the issuance and delivery of Warrant Shares upon exercise of this Warrant; provided, however, that the Corporation shall not be required to pay any tax which may be payable in respect of any transfer involved in the

registration of any certificates for Warrant Shares or Warrants in a name other than that of the

Holder or an Affiliate thereof.

(ii) Delivery of New Warrants

Upon Exercise. If this Warrant shall have been exercised in part, the Corporation shall, at the request of a Holder and upon surrender of this Warrant certificate, at the time of delivery of the Warrant Shares, deliver to the Holder a new

Warrant evidencing the rights of the Holder to purchase the balance of the unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant.

(iii) Rescission Rights. If the Corporation fails to cause the Transfer Agent to transmit to the Holder the Warrant

Shares pursuant to Section 1(e)(d)(i) hereof by the Share Delivery Date, then the Holder will have the right to rescind such exercise.

(iv) Compensation for Buy-In on Failure to Timely Deliver Warrant Shares Upon Exercise. In addition to any other rights

available to the Holder, if the Corporation fails to cause the Transfer Agent to transmit to the Holder the Warrant Shares pursuant to an exercise on or before the Share Delivery Date, and if after such date the Holder is required by its broker to

purchase (in an open market transaction or otherwise) or the Holder s brokerage firm otherwise purchases, Common Shares to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such

exercise (a Buy-In ), then the Corporation shall (A) pay in cash to the Holder the amount, if any, by which (x) the Holder s total purchase price (including brokerage commissions, if any) for the Common Shares so

purchased exceeds (y) the amount obtained by multiplying (1) the number of Warrant Shares that the Corporation was required to deliver to the Holder in connection with the exercise at issue times (2) the price at which the sell order

giving rise to such purchase obligation was executed, and (B) at the option of the Holder, either reinstate the portion of this Warrant and equivalent number of Warrant Shares for which such exercise was not honored (in which case such exercise

shall be deemed rescinded) or deliver to the Holder the number of Common Shares that would have been issued had the Corporation timely complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases Common Shares

having a total purchase price of US$11,000 to cover a Buy-In with respect to an attempted exercise of shares of Common Shares with an aggregate sale price giving rise to such purchase obligation of US$10,000, under clause (A) of the immediately

preceding sentence the Corporation shall be required to pay the Holder US$1,000. Notwithstanding the foregoing, the Corporation shall not be required to make the payments set forth herein in the case of uncertificated Warrant Shares if the Holder

fails to timely file a request with the DTC to receive such uncertificated Warrant Shares. The Holder shall provide the Corporation written notice indicating the amounts payable to the Holder in respect of the Buy-In and, upon request of the

Corporation, evidence of the amount of such loss. Nothing herein shall limit a Holder s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or

injunctive relief with respect to the Corporation s failure to timely deliver the Warrant Shares as required pursuant to the terms hereof.

(v) No Fractional Shares or Scrip. No fractional shares or scrip

representing fractional shares shall be issued upon the exercise of this Warrant. As to any fraction of a share which the Holder would otherwise be entitled to purchase upon such exercise, the Corporation shall, at its election, either pay a cash

adjustment in respect of such final fraction in an amount equal to such fraction multiplied by the Exercise Price or round up to the next whole share.

(vi) Charges, Taxes and Expenses. Issuance of Warrant Shares shall be made without charge to the Holder for any issue or

transfer tax or other incidental expense in respect of the issuance of such Warrant Shares, all of which taxes and expenses shall be paid by the Corporation, and such Warrant Shares shall be issued in the name of the Holder or in such name or names

as may be directed by the Holder; provided, however, that in the event Warrant Shares are to be issued in a name other than the name of the Holder, this Warrant when surrendered for exercise shall be accompanied by the Assignment Form

attached hereto duly executed by the Holder and the Corporation may require, as a condition thereto, the payment of a sum sufficient to reimburse it for any transfer tax incidental thereto.

(vii) Closing of Books. The Corporation will not close its shareholder books or records in any manner which prevents the

timely exercise of this Warrant, pursuant to the terms hereof.

(f) Holder s Exercise Limitations. The

Corporation shall not effect any exercise of this Warrant, and a Holder shall not have the right to exercise any portion of this Warrant, pursuant to Section 1 hereof or otherwise, to the extent that after giving effect to such issuance after

exercise as set forth on the applicable Notice of Exercise, the Holder (together with the Holder s Affiliates, and any other Person acting as a group together with the Holder or any of the Holder s Affiliates), would beneficially own in

excess of the Beneficial Ownership Limitation. For purposes of the foregoing sentence, the number of Common Shares beneficially owned by the Holder and its Affiliates shall include the number of Common Shares issuable upon exercise of this Warrant

with respect to which such determination is being made, but shall exclude the number of Common Shares which would be issuable upon (i) exercise of the remaining, non-exercised portion of this Warrant beneficially owned by the Holder or any of

its Affiliates and (ii) exercise or conversion of the unexercised or non-converted portion of any other securities of the Corporation (including, without limitation, any other Common Shares Equivalents) subject to a limitation on conversion or

exercise analogous to the limitation contained herein beneficially owned by the Holder or any of its Affiliates. Except as set forth in the preceding sentence, for purposes of this Section 1(f), beneficial ownership shall be calculated in

accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended (the Exchange Act ), and the rules and regulations promulgated thereunder, it being acknowledged by the Holder that the Corporation is not

representing to the Holder that such calculation is in compliance with Section 13(d) of the Exchange Act and the Holder is solely responsible for any schedules required to be filed in accordance therewith. To the extent that the limitation

contained in this Section 1(f) applies, the determination of whether this Warrant is exercisable (in relation to other securities owned by the Holder together with any Affiliates) and of which portion of this Warrant is exercisable shall be in

the sole discretion of the Holder, and the submission of a Notice of Exercise shall be deemed to be the Holder s determination of