Greipel was on the outer at Lotto Soudal after it became known that Australian sprinter Caleb Ewan would be leaving Mitchelton-Scott to ply his trade at the Belgian team.
The 36-year-old German is the second big-name signing in as many years for the French squad, joining climber Warren Barguil for the next two years.
"I'm looking to win races and take on new challenges," Greipel said. "Cycling is a team sport, to win you have to have a strong team and I will strive to help this talented young generation while pursuing my personal goals.
"Next season, I want to be at 100 per cent of my abilities. I want to bring my sporting qualities but also my personality and my experience. I look forward to discovering my new role in this new environment."
The news that Greipel would take his bulging palmares to another team in 2019 came during the Tour de France where he abandoned along with many of the key sprinters.
Lotto Soudal team boss Marc Sergeant paid respect to Greipel for his commitment and leadership at the team.
“Everyone in this team, each rider and staff member, knew André as a gentleman," Sergeant said. He gained respect for his personality, and of course for his achievements, not for empty words.
"He made a big evolution since 2011. In the beginning, he was mainly a sprinter, but through the years he evolved into a real leader. He called us his family, and he meant it.”
Greipel will spend most of his time racing in France but his presence will give a boost to Fortuneo-Samsic which depends on wildcard invites to major races like the Tour de France. It also means fans will almost certainly seem him again at the start line for the 2019 Tour.