Have you made your own translation or installed one from OpenERP?

Own Translation:

You can export a file from settings > translations > import/export. Once exported you can substitute your own nomenclature/language in the .CSV and re-import the file. Remember to set the language in the settings > translations >languages menu.

From OpenERP:

From the menu settings > translations > load languages you can install a new language. I imagine you have to select the 'Overwrite existing terms' check box for all changes to take effect. Again, make sure the correct language is set for the user.

Edit: I don't speak French very well so unfortunately I cannot check the comprehensiveness of the French translation. However I just installed Danish, and it seems that only some of the modules are translated. However in those that were the nomenclature was changed. I would assume French would have a more comprehensive translation so maybe you didn't check the box to overwrite existing or change the user settings.

To be completely certain the translation is as you want it to be, I would recommend export/importing your own translation.

OpenERP uses a collaborative translation system.

You can access it on Launchpad: http://translations.launchpad.net/openobject-addons (for all the addons)

You can make translation proposals for words or sentences, then French reviewers have to validate your proposals. And when it's validated, it will be included into the official package.