ADR PROGRAM

How to hold sanofi-aventis ordinary shares shareholders can decide whether to hold their sanofi-aventis ordinary shares as bearer shares, administered registered shares or fully registered shares. We have appointed BNP Paribas Securities Services (BNP Paribas) as agent to administer our fully registered shares. How to hold sanofi-aventis ordinary shares shareholders can decide whether to
hold their sanofi-aventis ordinary shares as bearer shares, administered
registered shares or fully registered shares. We have appointed BNP Paribas
Securities Services (BNP Paribas) as agent to administer our fully registered
shares.

Converting shares into registered shares

If you hold bearer shares, you can convert them into fully registered shares by asking your financial intermediary to transfer them to BNP Paribas. A transfer form for French and foreign banks is available on our website www.sanofiaventis.com/shareholders or on request (see our contact details on page 23). Once you have signed a brokerage services agreement with BNP Paribas, you will be given a confidential code for carrying out transactions by mail, fax or telephone, or over the Internet (see details). If you hold bearer shares, you can convert them into fully registered shares by
asking your financial intermediary to transfer them to BNP Paribas. A transfer
form for French and foreign banks is available on our website
www.sanofiaventis.com/shareholders or on request (see our contact details on
page 23). Once you have signed a brokerage services agreement with BNP Paribas,
you will be given a confidential code for carrying out transactions by mail,
fax or telephone, or over the Internet (see details).

If you hold bearer shares and want them to be held as administered registered shares, ask your financial intermediary to carry out a transfer. See ADR information for US holders on pages 20-21. If you hold bearer shares and want them to be held as administered registered
shares, ask your financial intermediary to carry out a transfer. See ADR
information for US holders on pages 20-21.

BNP PARIBAS SECURITIES SERVICES

Global Corporate Trust Émetteurs Actionnariat sanofi-aventis Immeuble “Europe” 9, rue du débarcadère 93761 Pantin Cedex France Toll-free number in France 0 800 87 74 32 Phone for international callers: +33 (0)1 40 14 80 40 Fax: +33 (0)1 55 77 34 17 GISnomi website: https://gisnomi.bnpparibas.com (ID code and password required) Global Corporate Trust Émetteurs Actionnariat sanofi-aventis Immeuble “Europe”
9, rue du débarcadère 93761 Pantin Cedex France Toll-free number in France 0
800 87 74 32 Phone for international callers: +33 (0)1 40 14 80 40 Fax: +33
(0)1 55 77 34 17 GISnomi website: https://gisnomi.bnpparibas.com (ID code and
password required)