Atmosphère is mentioned under Bib Gourmand in the 2011 Michelin Guide. It is located in the “basement” of a building which faces the main city square.  The “basement” has on the other side a waterfront view of the river Arve.
We arrived without a reservation and were glad they seated us.  I heard English spoken somewhere in the dining room and there was a Japanese couple.  Then, a party of at least 20 French people (not local) came to celebrate a birthday.  I believe it is not a foreign tourist trap.
We really enjoyed our evening meal there and recommend it. Agreeably priced. Not fancy but solid continental fare.
Carpaccio of tomato with “Burrata” and Basil  (heirloom tomato)

Preserved rabbit terrine with tomato jam and spices

Braised veal brisket

Roast breast of duck, pepper sauce

Three cheeses and salad (Beaufort, Reblochon, but I cannot remember the third) at the end.

The restaurant is located next to the River Arve, just above the surface of the water. Must be nice during the day.