Billie Jean King said female players are treated like "second-class citizens" as she joined in the criticism of the scheduling at this year's French Open.

Tournament director Amelie Mauresmo has apologised for describing women's matches as "less appealing" than men's.

"You want to make everyone feel important," tennis icon King said.

King, a 39-time Grand Slam champion in singles and doubles, is a long-time advocate for gender equality and is one of the founders of the Women's Tennis Association (WTA).

The American said women's matches should be played in primetime slots, with "equal opportunity" given to both genders.

"They should have the same amount of women's matches as they do men's. Real easy," King said before Saturday's women's final.

"If [they] keep treating us like second-class citizens we will stay second-class citizens.

"We should have more matches, but I think Amelie will take care of that next year. Knowing her, she's a winner."

Former Wimbledon and Australian Open champion Mauresmo said her initial comments about the scheduling were taken out of context.

However, she apologised to the players and said the tournament would try and find a better solution for next year's event.

King added the key to better scheduling would be for men to play best-of-three sets at Grand Slams.

"I have been saying forever we should only play two out of three sets. As the players get older, I want them to be able to play," King said.

"Nadal is one - do you want him to stop? I never want him to stop. I want to make it possible for them to win."

King was awarded France's highest civilian honour - the Legion of Honour - on Friday and was also honoured on court at Roland Garros.

She was in attendance at the women's final to see Iga Swiatek beat Coco Gauff for her second Grand Slam title.