PRESS RELEASE Paris

Paris, April 27, 2012

Strong performance in Q1 2012 including Genzyme contribution

In order to facilitate an understanding of our operational performance, we comment on our business net

income statement. Business net income1 is a non-GAAP financial measure. The

consolidated income statement for Q1 2012 is provided in Appendix 7. A reconciliation of business net income to consolidated net income is provided in Appendix 6. Consolidated net income for Q1 2012 was 1,827 million, compared to

1,218 million for Q1 2011. Consolidated EPS for Q1 2012 was 1.38 versus 0.93 for Q1 2011.

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2012 first-quarter net sales

In the first quarter of 2012, Sanofi generated sales of 8,511 million, up 9.4% on a reported basis. Exchange rate movements had a positive effect of 2.4 percentage points reflecting the appreciation of the U.S. dollar, the Japanese Yen and the Chinese Yuan

against the Euro. At constant exchange rates, and adjusting for changes in the scope of consolidation (primarily the consolidation of Genzyme), net sales decreased by 0.6%.

Growth Platforms (see Appendix 4)

Sales of the Group s growth platforms (including new

Genzyme ) were 5,381 million, an increase of 14.8%, or 5.7% with Genzyme pro forma. Diabetes and Consumer Health Care grew at a

double-digit pace in the quarter. Sales of new Genzyme , which were not consolidated in the first quarter of 2011, also increased at a double digit rate. The Group s growth platforms accounted for 63.2% of total consolidated sales in

the first quarter of 2012, up from 59.2% in the first quarter of 2011.

First-quarter sales for the Pharmaceuticals business were 7,316 million up 8.8%, which reflects the positive contribution from Genzyme (consolidated from April 1, 2011) as well as the negative effect of generic competition on Lovenox ,

Ambien CR and Taxotere in the U.S.; Plavix and

Taxotere in the EU, and the impact of EU austerity measures.

Diabetes business increased 14.4% to 1,311 million driven by the performance of Lantus (up 17.2% to

In the U.S., sales of Lantus grew 16.5% to 684 million, with

Lantus SoloSTAR representing 51.1% of total

Lantus sales in the quarter, versus 43.8% in the first quarter of 2011. In Emerging Markets, sales of Lantus reached

181 million, an increase of 32.4%, reflecting the robust performance in China (up 64.1%), Brazil (up 30.4%), Russia (up 34.7%) and

In Japan, sales of the product recorded double digit growth (up 14.6% to 32 million).

Sanofi is sponsoring a large-scale, methodologically robust epidemiology program as agreed with

the European Medicines Agency (EMA) and shared with health authorities worldwide, the program includes three large studies including two retrospective cohort studies and one case-control study conducted by independent investigators. The results of

the Northern European Database Study of Insulin and Cancer Risk - the first of the retrospective cohort studies - have been reviewed by EMA. The results of the U.S. database, a retrospective cohort study in the Northern and Southern

California Kaiser Permanente (KP) diabetes registries, will be reviewed by Health Authorities in the next few weeks. Both studies will be presented at a scientific session of the American Diabetes Association in June 2012. The results of these two

studies confirm Sanofi s confidence in the safety of Lantus . The third study, a case-control study, is

ongoing and expected to deliver results according to schedule.

Sales of the rapid-acting insulin analog Apidra were

52 million, up 4.1%, and reflected an improvement in supply of the Apidra 3mL cartridges. The production of

Apidra 3mL cartridges will return to full capacity in second quarter of 2012.

Amaryl decreased 7.4% to 103 million. The impact of generic competition in Japan (sales down 29.1% to 31 million) was

partially offset by the growth in Emerging Markets (sales up 7.0% to 62 million).

Sales from the Oncology

business were 741 million, an increase of 12.8%, driven by a strong quarter of Eloxatin in the U.S. with sales of 321 million (up

158.8%) and consolidation of sales from ex-Genzyme oncology brands (up

+8.4%* to 133 million).

September 2011, the U.S. District Court for the District of New Jersey ruled against Sun Pharmaceuticals in favor of Sanofi U.S. with respect to a contractual dispute arising from the resolution of the

Eloxatin patent litigation. This ruling, under appeal, supports the U.S. market exclusivity of Eloxatin through August 9, 2012.

Taxotere sales continued to decline and were down 61.8% to 150 million, impacted by generic erosion in the U.S. (sales were down 91.1% to

15 million) and Western Europe (sales were down 74.3% to 19 million).

Sales of Jevtana were 54 million, up 10.4%. Sales in the U.S.

and Western Europe reached 28 million and 19 million, respectively.

Worldwide presence1 of Plavix /Iscover

The Worldwide presence of Plavix decreased by 2.5% to 1,763 million, impacted by

generic competition in Europe (down 18.6% to 124 million). Sales in the U.S. (consolidated by Bristol-Myers Squibb) were 1,245 million, down 0.5%. Consolidated sales in Emerging Markets were 191 million (up 5.2%), of which 87 million generated in China (up 23.7%). Plavix continued to grow in Japan (sales increased 11.9% to 168 million).

Worldwide presence of Plavix /Iscover

Worldwide presence1 of

The Worldwide presence of Aprovel was

404 million, down 18.1% due to generic pressures affecting the class. U.S. sales declined 37.0%, reflecting the loss of exclusivity

on March 30, 2012. Sanofi launched an authorized generic in the U.S. Consolidated sales of the product in Emerging Markets reached

97 million, up 1.1%.

Worldwide presence of Aprovel /Avapro /Karvea : geographic split

Other Pharmaceutical Products

Lovenox sales reached

526 million, down 10.5%, reflecting generic competition in the U.S.

( 122 million, down 46.8%). Outside the U.S., sales of Lovenox grew 11.9% to 404 million, with good performance

recorded in Western Europe (up 8.2% to 225 million) and Emerging Markets (up 18.9% to

154 million). In the U.S., sales

( 122 million) plateaued compared to the fourth quarter of 2011. Sanofi sells also an authorized generic of Lovenox in the U.S. (sales are booked in the Generic business).

63 million, down 3.2%, reflecting the impact of updated labels in the second half of 2011.

Ambien family of products were 125 million, up 1.7%, reflecting generic competition to Ambien CR in

the U.S. and Western Europe. In Japan, sales of Myslee increased 5.9% to 73 million. Competing generic products are likely to enter this market in the second half of 2012.

sales as a prescription drug decreased 20.4% to 182 million, reflecting the impact of a mild and late allergy season in Japan

compared to 2011. Sales of the product in Japan were down 22.9% to 153 million. In December 2011, the Japan patent office found two

Japanese patents covering Allegra invalid. This decision was subsequently appealed by Sanofi. Competing generics

of Allegra may possibly enter the Japanese market in the second half of 2012 if the generic manufacturers receive

marketing approvals.

Consolidated sales of Copaxone were 24 million compared to 114 million in the first quarter of 2011 reflecting the transfer of the Copaxone business to Teva in all remaining countries in the first quarter of 2012. Following the transfer, Sanofi will receive a payment of 6% on sales from Teva for a

period of two years, on a country-by-country basis.

Sales of Renvela /Renagel were 147 million, an increase of 8.4%, due to continued U.S. market share growth (U.S. sales were up 18.1% to 102 million).

First-quarter sales of

Synvisc /Synvisc One were 78 million, up 8.7%*, led by strong

performance of the Synvisc One franchise in the U.S. (Synvisc /Synvisc One sales were up

18.9%* to 66 million in the U.S.)

At the beginning of April, Sanofi has completed the acquisition of Pluromed Inc., a medical device. Pluromed has developed a proprietary polymer technology, called Rapid Transition Polymers, pioneering the use of

injectable plugs to improve the safety, efficacy and economics of medical interventions. Sanofi will commercialize Pluromed s

LeGoo , a highly innovative FDA approved and CE marked gel for temporary endovascular occlusion of blood vessels

during surgical procedures.

New Genzyme currently consists of Rare Diseases products and future Multiple Sclerosis products (AubagioTM and LemtradaTM).

New Genzyme sales were 400 million, an increase of 13.7% compared to non consolidated sales in the first quarter of 2011.

Sales of Cerezyme were

149 million, an increase of 5.8%. The reduction in global supply continued to impact sales at the beginning of the quarter. In

February 2012, Genzyme started to provide full supply for patients in the U.S. As a consequence, sales of the product in the U.S. reached

36 million in the first quarter of 2012 compared to 25 million in the fourth quarter of 2011.

Sales of Myozyme /Lumizyme

reached 112 million, an increase of 17.0% driven by continued expansion of Lumizyme in the U.S. and volume growth across all geographies.

Fabrazyme were up 50% to 47 million of which 10 million was generated in Western Europe (up 42.9%) and 23 million in the U.S. (up 69.2%). In March 2012, Genzyme began shipping Fabrazyme produced in its new plant in Framingham MA, which was approved by the Food and Drug Administration and the European Medicines Agency in January 2012. In March,

patients in the U.S. returned to full dosing. In addition, all new patients in the U.S. are eligible to begin

Fabrazyme treatment, at full dosing levels. In Europe, the process of moving the most severely affected patients

to full dose of Fabrazyme began in March 2012. Globally, the complete return to normal supply levels of