Before making suggestions, I'd like to know a little more such as:
Is the club is metting at your house this time?
How much last minute cooking are able or willing to do?
How large is your group?
What's your budget?
Will your group do seafood?
Will supper be indoors or out?
Will you have access to a grill? (Always a great for summer cooking)
Are you looking for something seasonal and light?
If I were cooking and had a grill available, I'd orient the meal towards the Riviera do a simple grilled fish or lamb chop (frenched of course!), have some sort of olive sauce, or even just a tapenade ready to go, and serve on plates garnished with ratatouille.
Pete suggested several stews and casseroles. They're on the hearty-winter-meal side, but certainly scream "French," and may be just what the doctor ordered for your group.
A couple of French classics, a little lighter, and which may be entirely prepared ahead, are duck in tomato and green olives (Riviera regional), and Chicken Marengo (an impromtu invented for Napoleon to commemorate his victory at, you guessed it, Marengo).