The Frenchman salvaged the king of the mountains title and 15th place overall from a trying Tour de France in July and has since decided that the final stage on the Champs-Élysées would be the final act of his 2019 campaign.
"Despite the joy of winning the polka-dot jersey as the best climber of the Tour de France, the 2019 season did not reach the goals I set for myself," Bardet said in a statement released by AG2R La Mondiale.
"After a few days of personal reflection and discussions with the management of the AG2R La Mondiale team, it became clear to me that I needed to recharge myself physically and mentally to come back stronger next season. The level of competitiveness that I want to reach requires freshness in all areas."
Bardet struggled to find his best form through the spring, where his best results were 2nd at the Tour du Haut Var and 5th at Paris-Nice. In June, he placed 10th at the Critérium du Dauphiné, before finishing second in the inaugural Mont Ventoux Dénivelé Challenge.
At the Tour de France, Bardet never looked like replicating the kind of displays that carried him to the podium in 2016 and 2017. He conceded early ground on the first summit finish at La Planche des Belles and although he made a game attack on home roads in Brioude on July 14, his challenge ended definitively on the slopes of the Col du Soulour on stage 14.
On the Tour's second rest day, Bardet was already making plans for 2020, vowing to make changes to a racing programme that has been markedly similar for the past six years.
Bardet put a different slant on his Tour with an aggressive showing in the final week, and he managed to secure the polka-dot jersey after going on the attack on the road to Valloire on stage 18.
"I will take advantage of the next few weeks to rest, while continuing to remain physically active, and define the contours of a 2020 season that looks already very exciting," Bardet said. "I thank the team, staff, team partners, and the fans for their trust in me and support throughout the season."
It remains to be seen how Bardet's programme will change in 2020. The 28-year-old has been linked with a possible Giro d'Italia debut, though on Friday, team manager Vincent Lavenu suggested that next season's plans have yet to take shape.
"After conscientiously analyzing his season with the sports and medical staff, it appeared that it was necessary for Romain to put an end to his racing in 2019," Lavenu said. "It is a thoughtful and well-considered decision that will allow us to define with him the profile of the 2020 season and its goals, which will be high as always."