I was gonna say, if you are happy going non-stop VFR on top (ca existe en France?), then you stand a good chance of success. I go UK to Samedan several times a year, and the weather actually in the mountains is often clear as a bell, (but that's in a twin-jet, able to divert to Zurich IFR if need be, or indeed a multitude of en route alternates too. I'm not sure I'd be comfortable doing the same in a VFR piston single.)
If however, you choose normal below cloud VFR, then keep a watch on orbifly's met map and see how often (or not)! there are green VFR blobs along the entirety of your route in winter.
Sorry to be the pessimist.