Hi,
If you travel to France in the spring, rates are cheaper and there are less tourists, too, so that may work out better for you. I've been there in March, April, and in June and in September/October, and I like the off summer months. You don't list your interests, your ages, or how active you two are, so it's difficult to give rock solid advice. It appears you don't have a car, either.
Based on that, four full days and nights in Lyon might be a day too much as you could do it in three: it's a beautiful City, especially at night. Walking along the Rivers while seeing the City lit up is a beautiful scene. There's plenty to see and do during the day, too: great Roman ruins, at least two great museums (Fine Arts and Confluence), the old Town, Notre Dame, the Parc Tete d'Or, and of course, the world famous food and wine. I've been there three times and really enjoy the City.
I haven't been to Toulouse, so I can't comment. Off the top of my head, six days there seems like a lot, though, especially if you don't have a car. Have you considered taking the train from Lyon south to Arles/Avignon and or Nimes and then on to Toulouse? All three are beautiful and easily worth two to three days each. And all of them are about an hour apart. And you don't have to go to all three. That is a route I took a few years ago and had no regrets. When you eventually end up in Toulouse, I would absolutely take the one hour train trip to Carcassonne. It is a magnificent medieval city and easily worth a full length day there.
As for Bordeaux, I spent five or six nights there and loved it. That was sufficient for me. However, I'm a VERY big wine fan so I spent three full days touring vineyards in St. Emillion and the Medoc drinking wine. If I'm not mistaken, about 67 % of Bordeaux's economy is derived from wine sales, tourism, etc. so that is certainly the main draw there. The restaurants in Bordeaux were excellent and there were plenty of great wine bars, too. The opera and the Fine Arts museum were both excellent. When you get to St Emillion, make sure you get into see the Monolithic Church there.
Finally, if you are adamant on spending 25 days in those five cities you identify, I would spend more time in Paris than anywhere else. It is truly one of the greatest cities in the world with so much to do and see. Not only that, there are fantastic day trips that you can take from Paris: Rouen, Giverny, Chartres, Versailles, Fountainbleu, etc. and still see the City.
Best of luck