Gallopin will head into the race as a big chance to feature in the finale, while Bouhanni will hope to survive to contest any possible sprint finish.
Gallopin, who won the 11th stage of the 2014 Tour de France is a punchy rider who will suit the terrain of the Ponferrada, Spain course.
Bouhanni enjoyed a breakthrough season this year, winning three stages of the Giro d'Italia and claiming two stage wins on the Vuelta a Espana.
But the 24-year-old was suspended by his FDJ team earlier this month after he publicly criticised the staff.
He will leave the team at the end of the season.
Gallopin and Bouhanni will compete in the road race on 28 September alongside Tour de France runner-up Jean-Christophe Peraud, Romain Bardet, Cyril Gautier, Sylvain Chavanel, Warren Barguil, Kevin Reza and Julian Alaphilippe.
Jerome Coppel and Chavanel will represent France in the time trial.
The first five days of the UCI Road World Championships will be live-streamed on the Cycling Central website, while the final two days will be broadcast on SBS ONE and streamed online.