The home side took the lead after 16 minutes, however, when Gael Danic curled a free kick into the top corner.
Marseille began to take control of possession as the half developed, but Benoit Cheyrou fired an effort wide of the target before the 30-minute mark.
Both sides had chances in the latter stages of the half, but it was the home side who added a second 10 minutes before the break when Le Tallac converted from close range.
Valenciennes were not finished there, however, and they added a third through Foued Kadir just before the interval.
The home side continued to dominate in the early stages of the second period and Le Tallac came close to his second with a powerful effort on the hour mark.
The former Liverpool man did not have to wait long to make amends, however, and he added his side's fourth of the afternoon with a header from close range.
The away side threatened to open their account as the match approached its latter stages and Ayew grabbed a consolation strike for Marseille in stoppage time.