Company: SNY
Filing Date: 2025-10-27
Form Type: 424B5
Source: 0001193125-25-250786
Chunk: 121

Company: Sanofi
Filing Date: 2025-10-27
Form: 424B5
Chunk 121
---
” exceeds a certain threshold. If required, this disclosure is made by filing Form 8938 with the U.S. Internal Revenue
Service. Significant penalties can apply if you are required to make this disclosure and fail to do so. In addition, you should consider your possible obligation to file online a FinCEN Form 114 — Foreign Bank and Financial Accounts Report as
a result of holding debt securities. The application of these reporting requirements is not entirely clear. You are thus encouraged to consult your U.S. tax advisor with respect to these and any other reporting requirement that may apply to your
acquisition of debt securities.

Information Reporting and Backup Withholding

The paying agent must file information returns with the U.S. Internal Revenue Service in connection with debt security payments made to certain
United States persons. If you are a United States person, you generally will not be subject to United States backup withholding tax on such payments if you provide your U.S. taxpayer identification number to the paying agent. You may also be subject
to information reporting and backup withholding tax requirements with respect to the proceeds from a sale of the debt securities. If you are not a United States person, you may have to comply with certification procedures to establish that you are
not a United States person in order to avoid information reporting and backup withholding tax.

37

PLAN OF DISTRIBUTION We may sell the debt securities offered by this prospectus:

| • |     | through underwriters; |

| • |     | through dealers; |

| • |     | through agents; or |

| • |     | directly to purchasers. |

The prospectus supplement relating to any offering will identify or describe:

| • |     | any underwriter, dealers or agents; |

| • |     | their compensation; |

| • |     | the estimated net proceeds to us; |

| • |     | the purchase price of the debt securities; |

| • |     | the initial public offering price of the debt securities; and |

| • |     | any exchange on which the debt securities will be listed, if applicable. |

Underwriters If we use underwriters in the sale, we will enter into an underwriting agreement. The underwriters will acquire debt securities for their own account and may resell the debt securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Unless we otherwise state in the prospectus supplement, various conditions to the underwriters’ obligation to purchase