Degenkolb was tipped as a strong favorite after winning the Paris-Bourges race on Thursday. Demare made his move on the Avenue de Grammont but was overtaken by the powerful Argos-Shimano rider, who earned his sixth victory of the season.
"He raced a really classy race," Argos-Shimano manager Christian Guiberteau said. "He was the top favorite, and that's not an easy position to be in. But he was always in control in the finale and no one could stop him in the end."
Bryan Coquard of France, a 2012 Olympic runner-up in the omnium, fell in a crash about 24 kilometers from the finish. The Frenchman managed to get back on to his bike and rejoined the pack but was out of contention in the sprint.
In the first hour of the race, Sebastian Lander of Denmark, Aleksejs Saramotins of Latvia and Frenchmen Yannick Martinez and Julien Duval broke away to build a lead that stretched to 11 minutes. But the pack reeled them in with 11 kilometers left.