Pele was taken to hospital in Paris as a precaution after falling ill following a meeting with Kylian Mbappe, according to reports.
French radio station RMC Sport said the 78-year-old had a "crisis of tetany" (involuntary muscle cramps) as well as a fever, which resulted in him being kept in for observation.
Press Association Sport has approached representatives of the Brazilian three-time World Cup winner for comment.
Pele has struggled with health issues in recent years, pictured using a cane to aid his walking due to problematic hips and knees as well as suffering from a serious urinary tract infection.
The former striker pulled out of the opening ceremony of the 2016 Olympic Games in Rio de Janeiro due to unspecified health reasons.
Pele arrived at the draw for the 2018 World Cup using a wheelchair. During January last year, he was also unable to attend a tribute dinner held in his honour by the Football Writers' Association in London.
The Brazilian, regarded as the world's greatest player, had been able to travel to France earlier this week to meet with Mbappe as part of his ambassador role for a Swiss luxury watch brand.
Mbappe was one of the stars of Les Bleus' 2018 success in Russia, and followed Pele in becoming the second teenager to score in a World Cup final as Croatia were beaten 4-2.
Pele, part of the 1970 Brazil World Cup winning squad, feels there is yet more to come from the 20-year-old Paris St Germain forward.
"He is really fast, has the ability to think quickly, change his gesture at the last minute. This is something which challenges us all," Pele said to RMC Sport on Tuesday.
"Each player has his speciality, his own characteristic and he is very fast in his decision-making, it is one of his strong points."
