I believe they have serge aurier currently and before him Christophe Jallet. I follow PSG and can tell you neither of these players are CL caliber. Jallet is a solid Frenchmen but nothing more, Aurier was a WC stand out who wS bought from an African side (Ivory Coast I believe). Coleman would be an upgrade for them.
If we do this they have some great youngsters it would be better to trade for. Adrian rabiot is a great midfielder and Jean Christophe bahbeck is a fantastic forward.