Constantine II, AE follis, Lyons. 

DN CONSTANTINO IVN NOB C, laureate, draped, cuirassed bust right, 
seen from the back.
VICTORIAE LAET PRINC PERP, two Victories standing facing each
other, holding between them a shield inscribed VOT PR on an
altar decorated with a square (Helv. 4b).

Mintmark P-two captives back to back-L.

RIC VII Lyons 90.
Very rare, rated R5.