Cramps and tears as Medvedev beats brutal heat at Australian Open
The qualifier struggled in the searing heat on Margaret Court Arena, stunning the Russian by taking the first set but was unable to continue when trailing 5-7, 6-2, 6-4, 1-0.
"The conditions were brutal," said two-time tournament finalist Medvedev. "The more he (Atmane) plays this intensity, the better he will be prepared."
"I'm just happy to be through," he added. "I played bad at the beginning in the first set, but I was happy I could regain momentum."
Medvedev broke for 2-1 in the opening set and raced to 5-3, but a battling Atmane levelled the score at 5-5 when Medvedev missed a volley.
With his confidence building, the Frenchman, on his Grand Slam debut, held serve then broke again to take the set and leave the world number three shaking his head in disbelief.
Medvedev woke up to steam through the second set before Atmane started cramping badly.
He resorted to underarm serves as he struggled to move and demolished his racquet when he lost serve to slip 2-1 behind in the third set.
The 22-year-old gamely battled on, still in pain, mixing underarm and overarm serves as Medvedev cashed in to take the third set.
But after losing the first game of the fourth set, he was forced to retire, sobbing as his tournament ended.
Medvedev, who faces Finland's unseeded Emil Ruusuvuori in the next round, said ahead of the match he is trying to "mature" and do fewer "stupid things" on court to shake off his reputation as a tennis villain.
The Russian is no stranger to outbursts and meltdowns on court, which has earned him a love-hate relationship with fans.
He was mostly well behaved against Atmane, but did complain about the water bottles.
Medvedev lost to Novak Djokovic in the 2021 Melbourne final and Rafael Nadal a year later, which sparked a form slump.
But has since bounced back, winning 66 matches last season, more than any other player on tour.