Company: SNY
Filing Date: 2025-10-29
Form Type: 424B5
Source: 0001193125-25-255563
Chunk: 80

Company: Sanofi
Filing Date: 2025-10-29
Form: 424B5
Chunk 80
---
depositary, such as The Depository Trust Company, Euroclear Bank S.A./N.V. or Clearstream Banking, société anonyme, as specified in the applicable prospectus supplement.

Listing

If any debt securities are to be
listed or quoted on a securities exchange or quotation system, the applicable prospectus supplement will say so.

6

RISK FACTORS We urge you to carefully review the risks described below, together with the risks described in the documents incorporated by reference into this prospectus, before you decide to purchase debt securities. In particular, you should review the risks relating to our business included in our 2023 Form 20-F,incorporated by reference herein, and any similar disclosure in any subsequent report. If any of these risks actually occur, our business, financial condition and results of operations could suffer, and the trading price and liquidity of the debt securities offered by this prospectus could decline, in which case you may lose all or part of your investment. Risks relating to an investment in the debt securities We may incur substantially more debt in the future. We may incur substantial additional indebtedness in the future, including in connection with future acquisitions, some of which may be secured by our assets. The terms of the debt securities issuable hereunder and the indenture under which the debt securities are issued will not limit the amount of indebtedness we may incur. Any such incurrence of additional indebtedness could exacerbate the risks that holders of the debt securities currently face. At any point in time there may or may not be an active trading market for our debt securities. At any point in time there may or may not be an active trading market for our debt securities. While we may decide to list a particular series of debt securities on one or more stock exchanges or automated quotation systems, we generally expect that any debt securities issued pursuant to this prospectus will not be listed on any exchange or automated quotation system. If any of the debt securities are traded after their initial issuance, they may trade at a discount from their initial offering price. Factors that could cause the debt securities to trade at a discount include, among others:

| • |     | an increase in prevailing interest rates; |

| • |     | a decline in our credit worthiness; |

| • |     | the time remaining to the maturity; |

| • |     | a weakness in the market for similar securities; and |

| • |     | declining general economic conditions. |

Since the debt securities are unsecured, your right to receive payments