Romanian word apropo comes from French propos (Aim, intention. Remark.)

Detailed word origin of apropo

Dictionary entry	Language	Definition
propos	French (fra)	Aim, intention. Remark.
à propos	French (fra)	By the way. In connection, concerning, with regard, in reference. Opportunely, at the right time, just in time Opportune, advisable, fitting, appropriate, apropos.
apropo	Romanian (ron)	Hint. Innuendo By the way; speaking of which. Incidentally.