Maison can be used indeed as a synonym for a firm or an enterprise. It carries a positive connotation, and some prestigious businesses take pride in being called a “maison”.

It can be used for restaurants or caterers as you have found out, but also for some other types of business, such as in fashion (eg La maison Dior), or even for some “mom-and-pop” stores (this is where the shop is then usually named after the family, eg a grocerer named Dupont can christen his/her store maison Dupont).

Even outside of these usual areas of business, it is also common in phrases used to talk about years of service in a firm:

Il a vingt ans de maison (he has been working here for 20 years)

In large firms, the corporate seat can also be called la maison-mère.

Publishers can be also be called maison d’édition (ex: la maison d’édition Larousse)