Just a note that the Polytechnique bachelor in English is NOT the military branch - no cool 1804 style uniform with a sword for the Bachelor students and no salary (getting into Polytechnique is a very specific path -~90% come from only 5 preparatory schools and 80% are multiple legacies.
It’s harsh and academically very hard
Once admitted you are paid a nice salary and “owe” 10 years as an Engineer in one of the public companies, though that’s another way to say you’ve got a guaranteed job).
The BS program, as well as the other 2 École programs in English I listed, functions more like a British style “joint degree” in math. It’s international-friendly so, mixes high expectations with a more welcoming environment&lots of student-managed clubs and activities.