You're talking about the "FC" of Paris Saint-Germain FC, right ?
Yes
I think it hasn't been used since PSG FC splitted into PSG on one side and Paris FC on the other side, in 1972.
I never thought about it before, because I was sure all the time that Paris Saint-Germain FC has its unchangeable name since the creation in 1970 until the present day ))))
Actually, the real name of PSG is still PSG FC but it is usually called simply PSG.
Simply calling and the official embleme (logo) - rather different positions, I think.
Look at the past : all Paris SG logos with the inscriptions had 'FC' automatically.
It's a law, I think. Look at St-Etienne - ASSE, at Liverpool - Liverpool Football Club full inscription, at Real Madrid - CFRM, Milan - ACM...
So, the official logo must have full letters (or abbreviatures as a minimum).
Stade de Reims and Olympique de Marseille haven't added abbreviations like FC, SC, AS or something else. Yes - their logos are logically free of it. But we are Paris Saint-Germain Football Club, and for me it will be a real surprise, to see the new official embleme without the full name of the Club