Exhibit 12.1

 CHIEF EXECUTIVE OFFICER CERTIFICATION

 I, Frank E. Dangeard, certify that: 

| 1.  | I have reviewed this annual report on Form 20-F      of Thomson;                                                                                                                                                                                                                                                                |
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| 2.       | Based on my knowledge, this report does not contain any untrue statement        of a material fact or omit to state a material fact necessary to make        the statements made, in light of the circumstances under which such statements        were made, not misleading with respect to the period covered by this report; |
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| 3.       | Based on my knowledge, the financial statements,      and other financial information included in this annual report, fairly present      in all material respects the financial condition, results of operations      and cash flows of the company as of, and for, the periods presented in this      report;                 |
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| 4.       | The company’s other certifying officers      and I are responsible for establishing and maintaining disclosure controls      and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e))      for the company and have:                                                                                      |
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|     | a)                                                                                                                                                                                                                                                                                                                              | Designed such disclosure controls and procedures,      or caused such disclosure controls and procedures to be designed under our      supervision, to ensure that material information relating to the company,      including its consolidated subsidiaries, is made known to us by others within      those entities, particularly during the period in which this report is being      prepared; |
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|     | b)                                                                                                                                                                                                                                                                                                                              | Evaluated the effectiveness of the company’s      disclosure controls and procedures and presented in this report our conclusions      about the effectiveness of the disclosure controls and procedures, as of      the end of the period covered by this report based on such evaluation; and |
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|     | c)                                                                                                                                                                                                                                                                                                                              | Disclosed in this report any change in the company's      internal control over financial reporting that occurred during the period      covered by the annual report that has materially affected, or is reasonably      likely to materially affect, the company's internal control over financial      reporting; and |
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| 5.       | The company’s other certifying officers      and I have disclosed, based on our most recent evaluation of internal control      over financial reporting, to the company's auditors and the audit committee      of the company’s board of directors (or persons performing the equivalent      functions):           |
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|     | a)                                                                                                                                                                                                                                                                                                                              | All significant deficiencies and material weaknesses      in the design or operation of internal control over financial reporting      which are reasonably likely to adversely affect the company's ability to      record, process, summarize and report financial information; and |
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|     | b)                                                                                                                                                                                                                                                                                                                              | Any fraud, whether or not material, that involves      management or other employees who have a significant role in the company’s      internal control over financial reporting. |

 

| Date: June 3, 2005 |   | /s/ Frank E. Dangeard                                        |
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|               |   | Frank E. Dangeard       Chairman and Chief Executive Officer |