Hi @Fabrice OBRACZKA
Via translation tool, I get following content. Any misunderstanding, you may let me know.
To open the VBA environment in Excel 2003, please click Tools menu, select Macro > Visual Basic Editor. Or you can use Alt+F11 as the shortcut to quickly open the Visual Basic Editor.
Here is the reference: https://www.utsc.utoronto.ca/~wainbantin/a01s08/lectures/39Excel2003Macros.pdf
(Please Note: Since the web site is not hosted by Microsoft, the link may changed without notice. )
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.