Alternative
This is a well-known false cognate, but I have to mention it here because we find it quite often in translated texts.
In English, an alternative is a possibility, one of the possible choices.
in French, an alternative is the choice itself.
So we should translate alternative with words such as possibilité, solution, variante (for patents) but not with alternative.
there is no alternative -> il n’y a pas d’autre possibilité
an alternative would be to … -> une autre solution consisterait à …
As for the adjective, alternative can be translated with autre in most cases, and not with alternative (except when talking about electricity)
an alternative approach-> une autre approche
alternative medicine -> médecine parallèle