Learn French: Il est peut-être interdit de fumer ici. - It is maybe forbidden to smoke here.

Peut-être literally means 'can be' or 'may be'. It is made of peut (the 'he/she/it' form of pouvoir, meaning 'can') and être (to be). Together with a hyphen, they form the French word for 'maybe' or 'perhaps'!

Why is there a de before fumer?

In French, when you use the impersonal phrase il est (it is) plus an adjective like interdit (forbidden), you generally need the word de before the action verb that follows. That is why 'It is forbidden to smoke' is Il est interdit de fumer.

Does Il mean 'He' in this sentence?

No, here Il is an impersonal pronoun meaning 'It'. It is used just like in English when we say 'It is raining' or 'It is forbidden'. There is no specific person being talked about.

Why is fumer in its unconjugated dictionary form?

Because it follows the preposition de. In French, whenever a verb follows a preposition like de or à, it must stay in its infinitive (unconjugated) form. Here, fumer translates directly to 'to smoke'.