Belgian cyclist Antoine Demoitie died after he was hit by a motorbike following a fall during the Gent-Wevelgem race, local police has said.
Police said on Sunday an inquiry is going on to "determine the circumstances", reports Xinhua.
Demoitie, 25, was rushed to the hospital after the accident in Sainte-Marie-Cappel, northern France where he was admitted to an intensive care unit due to serious conditions.
Sunday's Gent-Wevelgem race saw cyclists battle strong winds as they tackled 10 climbs over a 243-km route, including two ascents of the Kemmelberg.
Former Belgian national champion Jens Debusschere was also hospitalised after he sustained a concussion following a heavy crash, his Lotto-Soudal team said.
The race was won by Slovakia's Peter Sagan.