Palace appointed Sage after his work at Lens attracted attention, but the London club have struggled to find consistency under their new head coach. Former PSG star Rothen has questioned both Sage's attitude and his decision to leave French football rather than remain at Lens for a Champions League campaign.
Speaking on RMC, Rothen accused the 47-year-old of behaving as though his achievements had placed him above criticism.
“He said everything and its opposite last season. In terms of his attitude, he thought too highly of himself. Congratulations on winning the French Cup with Lens,” Rothen said.
The pundit argued that Sage's public comments about recruitment at Palace contrasted with his approach during his time at Lens, where he had worked with a squad assembled by the club.
“What is funny today is that he complains to Crystal Palace that the recruitment is not at the level he expected, but at Lens it didn't bother him to say nothing about recruitment because he hadn't been involved in it,” Rothen said.
He acknowledged that Sage had done effective work with the players available to him at Lens, but suggested the coach had subsequently taken too much credit for the team's achievements.
“They gave him players, and he mixed everything together very well internally. But because he needed to pull the attention towards himself, because to me he is falsely modest, he said: ‘The year at Lens was magnificent.’”
Rothen's criticism centred on the decision to leave Lens for England. He believes Sage could have continued building his reputation in France, particularly with the prospect of Champions League football, rather than accepting the first major Premier League opportunity that came his way.
“Then a big English club comes to get him. That is when he thought too highly of himself. If you are confident in your own ability, you do things differently with your directors at Lens and you would have accepted playing in the Champions League with Lens,” Rothen said.
He continued by questioning whether Sage had sufficient experience of elite-level football to understand the implications of the move.
“But because he lacked experience and knowledge of top-level football, the first club made him an offer and then we were told that he couldn't turn down Crystal Palace.”
Rothen also challenged the idea that Palace represented an irresistible opportunity, pointing to the club's previous league finishes as evidence that Sage should have been realistic about the task awaiting him.
The criticism comes amid a difficult opening period in England. Palace have struggled for results, and Rothen believes the team's performances have not shown enough evidence of a collective response to their problems.
“What we see is that in the first 12 matches, he has won three and taken heavy defeats against teams in the bottom half of the table. For now, there is no reaction from the group because you are lacking a lot of things,” he said.
Rothen's comments are an outspoken assessment rather than an objective verdict on Sage's coaching. Nevertheless, they underline the scrutiny facing the former Lens manager as he attempts to establish himself in English football.
Sage now has to find a way to improve Crystal Palace's results and demonstrate that his move to the Premier League can deliver the progress both he and the club expected.