Le Petit Bonheur
You can't the fault the location and atmosphere - right in the centre of Mons, by a fountain. The menu comes in at about 15 euros and has a number of staple favourites. All dependable quality, straightforward Mons cuisine: unpretentious and reasonably priced. We love the hustle and bustle in the summer: in the winter, it's often the only place open in the evening.
A view to die for at 800m with uninterrupted views from Mons down to Cannes and Frejus, across the Esterel. On a clear day, they say you can see Corsica (I know a man who claims he has enjoyed this experience - although this single claim seems to be the industry-standard "my view is better than your view" weapon). Food is more elaborate than the Petit Bonheur, probably with more variety. If you can get a table on the terrace, then the Auberge is one of the finest spots in the world for the traveller to eat. There are two other restuarants in Mons. One we have never tried and one that sells pizzas etc. For a town that has not changed in 1,000 years and that has just acquired a dedicated, fulltime baker, this is a deluge.
Nestled in a narrow street, you'd have to know about Chez Barbaroux to find it. Good food, good service, reasonable prices. Popular with the inlaws.