Yeah, you are right pxeger1 1: niche (/NEESH/) doesn't have accent mark. (In French, the e without an accent mark is silent. According to some person on Quora . . . )
Silent at the end of a word only (and when it is part of a conjugaison or accord suffix such as -es or -ent).
Also, depending on the accent of a person, the ending "e" can be pronounced, but it's rare.