The 27-year-old made the switch after five seasons with the Radioshack/Trek Factory Racing family where he had spent his entire career.
"I’m excited to be joining AG2R for the next two seasons and I would like to thank Vincent Lavenu for the opportunity to be racing with his team, Sergent said.
"AG2R is known for its aggressive, attacking, never give up style of racing and I am looking forward to being a part of that."
A two-time Olympic bronze medallist in the team pursuit, Sergent specialises in the time trial and shorter stage races.
"I hope to continue to grow as a rider and to keep targeting time trials and shorter stage races, and helping the leaders on the team to achieve results as its something I enjoy," he said.
His best performance in 2015 was a third placing overall at the Driedaagse van West-Vlaanderen.