Nouns ending in -age are usually masculine.
The suffix often marks an action, a result, or a collection.
Is passage masculine or feminine?
lepassage
The rule behind it
98.8% of -age nouns are masculine
In context
Il y a un passage secret à gauche.
There's a secret path on the left.
Les hordes mongoles ravageaient tout sur leur passage.
The Mongol hordes wiped out everything in their path.
Ne mettez pas vos affaires dans le passage.
Don't put your things in the passage.