\newtheorem{theorem}{Théorème}[section] \let\thm\theorem
It didn't work. What i want is that The first level of the "section" is not centered, and bold. It doesn't work when i export to pdf. It come from latex? Because under lyx, it appears as left-aligned and bold...
Eric,
Oh!, right!, I misread your post. You had already solved the problem regarding the theorem label in French. Sorry! Concerning your second question, it does come from LaTeX. I believe that one can obtain what you are wanting, but I do not know how. Maybe, someone else on the list can help you. I know of a package called sectsty (explore it!), which may help you, but, honestly, I have never used it.
Paul