there is a very beautiful abbey in the french alps, situated in the middle of forest with brilliant accoustic for (overtone) flutes and also voice..
i stayd here for a while and dreamed away in sound...
I love France with their old romanic churches. I stay for a very long time in Taizé
Another beautiful place is a church in Romanshorn - Not in France but near the Alps in Switzerland. There is the Old Church of Romanshorn. http://www.klangreich.ch
near the bike tourline around the Bodensee - I was there in this small old church and couldn't leave it again because the place is so nice and silent with a very good hall.