What's the difference between these?

I've recently acquired these French 1 Franc coins but I can't figure out if they're "1 Franc (Signature "O. Roty") 1959-2001" or “1 Franc Semeuse (Piéfort) 1960-1985”

Vilager041

I've recently acquired these French 1 Franc coins but I can't figure out if they're "1 Franc (Signature "O. Roty") 1959-2001" or “1 Franc Semeuse (Piéfort) 1960-1985”

Piéfort (Piedfort) coins are much thicker. In this case, the circulation coin is 6 grams and the pattern is 12 grams.

N#6

N#253915

Piedfort coins are made in small quantities, not intended for circulation, and would be pulled out of circulation immediately if someone tried because of the thickness.