@marind Probably easiest to post to forums (can be in French) but what exactly are you (not) seeing? No Zotero icon at all, or it doesn't work, or sth else entirely?
@adam42smith Thanks ! Will have a look
@adam42smith My profile was corrupter. When using a new one, it works. It's a pity, I need to set up a completely new profile :-(
@marind see https://www.zotero.org/support/kb/no_toolbar_button#firefox then