This will be fantastic - classic mixtes almost always are, so I totally get what you're doing here and why!
But before you go ordering VO Porteur bars, be aware that their 23.8 and 22.2 options refer to the diameter at the grips -- the diameter at the clamp for those bars is always 25.4, and that will be an issue for French stems which usually want 25.0mm and that'll be just the beginning of your French-specific odyssey...
You might consider finding some original French porteur bars (eg. the Belleri ones that VO used to sell NOS and inspired their version) and those will be 25.0 at the clamp, and 23.8 at the grips to accept the classic reverse brake levers.
Last edited by niliraga; 09-07-19 at 06:11 AM.