Dominic Thiem says Serena Williams showed "a bad personality" after he was told to end a French Open news conference to make way for her.

A tournament official told the Austrian fourth seed to leave the room while he was speaking to reporters on Saturday.

"Every player has to wait. It shows a bad personality, in my opinion," Thiem told Eurosport.

Tournament director Guy Forget has apologised to Thiem, who faces Gael Monfils in the fourth round on Monday.

According to French newspaper L'Equipe, 23-time Grand Slam champion Williams was keen to fulfil her media obligations as soon as possible after her surprise third-round loss to fellow American Sofia Kenin, saying "put me in another room, smaller, but now".

Thiem complained to a tournament official at the time of the incident.

"What the hell? But it's a joke, really. What's the point of that, that I have to leave the room because she's coming?" he said.

The 25-year-old added on Sunday that he believed former world number one Williams had contravened the players' usual protocol.

"I wasn't angry or frustrated. Maybe for a couple of minutes or so. It is just the principle," he said. "It doesn't matter if it is me who sits in there, even if a junior is in there.

"I am 100% sure Roger Federer or Rafael Nadal would never do something like that."

Federer said he understood Thiem's frustration, adding that players who had won their match, as Thiem had just done against Uruguay's Pablo Cuevas, are usually given priority over those exiting the tournament.

"I don't know what went wrong but something went wrong for this to happen," the Swiss 20-time Grand Slam champion said.

"If I would have lost today against Leonardo Mayer, I would let him go first or decide when he wants to go to press as he's got a next match. My next match is far, far away. So that's just the way you go about it.

"There must have been a misunderstanding, or maybe they should have kept Serena still in the locker room, not waiting here in the press centre."