I would have to agree with Lucy about Annecy. It is a beautiful town in the French Alps with a large walkway around the lake. It looks like it is out of a picture postcard and it is also wonderful to take a boat cruise on the lake.

If you are a fan of Van Gogh you could stop by Arles which also has an excellently preserved Roman theatre and Stadium.

Have a great time as weather in April is quite good but without the crowds (as when I was there in 2001).

Tom, London, Canada