You don't have to have a strong religious faith to appreciate the tranquil atmosphere of Cathédrale Métropole St-François de Sales. Ask when the next service starts or when you can go for a wander through.
When you've spent a bit of time at this principal church in Chambery, why not make your way to Carre Curial, Chateau de Chambery, and Elephants Fountain? They're not far from Cathédrale Métropole St-François de Sales and also a favorite with travelers.