"There was indeed a problem," coach Raymond Domenech, who made Barthez his number one ahead of Coupet, told a news conference on Thursday.
"Gregory Coupet had the blues for a moment. He cracked. Such things can happen."
Domenech said Coupet had left the camp in the French Alps resort of Tignes with his family and luggage on Wednesday before changing his mind and returning to the team hotel.
"He decided to come back," Domenech said. "Nobody is making a big fuss about it. We had an explanation.
"You have to understand that the France team is more important than the interests of any individual. The problem has been sorted."
Barthez and Coupet took part in a training session on Thursday, hardly talking to each other.
A source close to the team said Coupet had argued with Domenech. The Olympique Lyon goalkeeper was apparently upset because Barthez failed to complete a hike up an Alpine glacier, saying he had a sore calf.
The players had left their four-star hotel on Tuesday for a mountain refuge where they spent the night.
On Wednesday morning, they roped up for a hike on icy terrain before being joined by their families for lunch. The idea was to help team bonding before the finals in Germany start on June 9.
Domenech said when he named his 23-man squad earlier this month that Olympique Marseille's Barthez would be France's number one goalkeeper at the World Cup ahead of Coupet.
A prominent member of the Olympique Lyon side that won a record fifth successive Ligue 1 title and reached the Champions League quarter-finals last season, Coupet had said that he felt he should be the number one.
Domenech still has to announce who will be in goal when France play Mexico in a warm-up game at the Stade de France on Saturday.
(Writing by Patrick Vignal in Paris)
