Froome was jeered by part of the crowd as he was chasing to catch a group featuring Bardet after suffering a mechanical problem.
The 15th stage was held in the Massif Central, not far from Brioude, Bardet’s hometown.
Asked about the incident on Sunday, Froome just said he could understand the massive support Bardet was getting in his area.
“I heard that Chris Froome had been abused at times during yesterday’s stage. I’m sorry about that,” the Frenchman told a news conference on Monday.
“He is a champion and he deserves respect. I respect him as an opponent and he does not deserve that kind of treatment.”
In the 2015 Tour de France, Froome was spat at and had urine thrown at him due to doping allegations.
Bardet is third...