Constantine I, as Caesar (AD 306?307), AE follis,  Lugdunum mint. 

FL VAL CONSTANTINVS N C, laureate, cuirassed bust 
right, seen from the back.
GENIO POP-VLI ROMANI, Genius standing left before lighted 
altar, modius on head, loins draped, holding patera and 
cornucopia, 
N in right field, 
Mintmark PLC. 

RIC VI 213b.

Contributed by Yuri Kabanov, November, 2007.