Nouns ending in -tion are feminine.
The suffix forms abstract nouns of action or state.
Is restauration masculine or feminine?
larestauration
The rule behind it
99.8% of -tion nouns are feminine
In context
Cet établissement est un restaurant de restauration rapide.
That shop is a hamburger shop.
Quel est ton restaurant de restauration rapide préféré?
What's your favorite fast food restaurant?
La restauration rapide peut créer la dépendance.
Fast food can be addictive.