Questions & Answers about Quand le film commence, on s’assoit sur le canapé.
This is a very common question.
In Quand le film commence, on s’assoit sur le canapé, the present tense suggests a habitual or general action:
- Whenever the movie starts, we sit down on the couch.
- When the movie starts, we sit down on the couch (as a routine)
So this sentence sounds like something that regularly happens.
If you were talking about one specific future movie, French would usually use the future in both parts:
- Quand le film commencera, on s’assiéra sur le canapé.
That is an important difference from English, which often uses the present after when for future meaning.