Lots of good advice above. In general, vintage bikes can provide excellent utility and value for commuting. However, I wouldn't recommend a French-sized vintage bike as a starter bike for someone inexperienced in bike mechanics and wanting immediately to put it into commuting service. The best bet would be any of the myriad Japanese brands, or, less numerous, good quality US brands such as Schwinn, Trek, or Ross, for example.
Bring your proposed vintage purchases and other C&V questions over to the C&V forum and I'm sure we can help you out with selecting a suitable vintage bike and preparing it for commuting.