I don't know what you mean about a savings for staying in Paris 10 days or five. Hotels don't give you a discount just because you stay a few days longer. Paris is probably more expensive than other places so no savings in that regard (for hotels). I would not want to stay in any hotel for 10 days, actually. When I've been in a city that long (probably only Paris), I do switch hotels to experience a different neighborhood for one thing. Also, just in case I am not that crazy about the first hotel. There are a lot of neighborhoods I like in Paris, and I won't travel far for dinner at night. Although not crucial, I also try to plan my activities around the area I'm staying (eg, if I plan a day trip to the north or east, I plan that for the days I'm on the Right Bank, etc).

That Beaujolais Nouveau thing is just a promotional stunt, you know, for that wine. I don't even like it that much but you can buy it all year. I do like Brouilly. But if he is really into that, you could even go to the epicenter for their special festival which really has more things on Nov 20th.

https://sarmentelles.fr/nos-evenemen...on/?version=EN

It's not too far from Lyon., to the NW. the town is named Beaujeu

But if you do that time in Normandy, you may not want to add more days down near Lyon (you have to drive to that town). It's the opposite direction from Normandy, of course.