David Beckham's Inter Miami have been fined a record $2m (£1.4m) for breaking Major League Soccer (MLS) rules, BBC reported.
An investigation was launched last year over the signing of France midfielder Blaise Matuidi from Juventus in 2020.
The MLS ruled last month that Inter Miami had breached regulations and announced its punishment on Friday.
The MLS said Matuidi had been paid more than was allowed, effectively giving the team four "designated players" last season rather than the permitted three.
Designated players' wages do not count towards the MLS salary cap.
Known as the 'Beckham rule', it was introduced when the ex-England captain joined Los Angeles Galaxy in 2007.
World Cup winner Matuidi, 34, had been wrongly categorised, as had the team's former defender, Colombian Andres Reyes, the investigation found.
"The violations also included undisclosed agreements that resulted in the underreporting of salary budget amounts for players Leandro Gonzalez Pirez, Nicolas Figal and Julian Carranzay," the MLS said.
The franchise has also received a reduction of $2,271,250 (£1.6m) in how much it can spend on players for the 2022 and 2023 seasons, with managing owner Jorge Mas fined $250,000 (£176,000) and former chief executive and sporting director Paul McDonough suspended to the end of the 2022 season.
The MLS said no players had committed any offences and were not investigated.
The fine is the highest in league history and MLS commissioner Don Garber said: "These sanctions reflect the severity of Inter Miami's violations."
"We have worked closely with MLS to address these issues and have made significant changes in our management structure," Mas said.
Inter Miami are managed by former England women's manager and Beckham's ex-Manchester United team-mate Phil Neville.