So, I assume this is a direct flight. DTW-CDG-DTW.

AF would be a A340-300, with 2-4-2 in economy. 15 bulkhead seats and the 19D and G middle aisle seats with no/half seat in front of them. No exit row seats.

DL would be A330-300, with 2-4-2 also. 8 bulkhead and 8 exit row seats and 32 Economy plus seats (the 4 bulkheads are included in the 32).

I am 6'3", so at 6'5" I would say Delta is better for you as a gold. More chance at getting more legroom.