Williams, 39, was looking to win a record 24th Grand Slam title at Roland Garros after reaching the US Open semifinals earlier this month.
She said the injury she suffered in New York had not recovered enough to make her compete in Paris.
“I managed to get a bit better result, but just looking long term at this tournament – ‘Will I be able to get through enough matches?’ – and so for me I don’t think I can do it and I struggle to walk, so it’s kind of a telltale sign that I should try to recover, “he told reporters Wednesday.
Walking with a limp
“For sure in the second set (of the first round match) I felt like I needed to walk with a limp and it wasn’t good,” said Williams, who won three titles in Paris.
“I had to focus on walking straight so I don’t limp. I’ve tried – I always give 100% and everyone knows – maybe even more than 100% if that’s possible.
“It comforts me. I think Achille is a real injury that you don’t want to play with because it’s not good if it gets worse. I think it’s one of the worst.”
The French Open was originally scheduled to start in May, but has been moved to a September start date amid the coronavirus pandemic.
Williams’ retirement means her next opportunity to equal Margaret Court’s 24 majors record will be the Australian Open, which begins in January.