French club Olympique Lyonnais cannot make any signings in the January transfer window and will be relegated from Ligue 1 at the end of the season if they are unable to address financial mismanagement.
France's National Directorate of Management Control (DNCG), the financial police of the French league, on Friday issued the punishment to John Textor-owned Lyon, who are fifth in the Ligue 1 standings.
As part of the punishment, Lyon will also have their payroll supervised by the DNGC.
Textor, who also partly owns Botafogo in Brazil, RVD Molenbeek in Belgium and Crystal Palace in England, is the majority stakeholder of Lyon through Eagle Football Group, a holding company listed in Paris.
"You shouldn't just look at Olympique Lyonnais, but the fact that we are a group that owns several clubs," Textor told French media on Friday.
"I'm confident in our figures and the good news is that the DNCG is independent, they are very intelligent people, accountants, financiers who can look at the figures.
"We're going to generate several million dollars in cash over the next few months, and we're in it for the long haul."
Lyon spent around 145 million euros ($153 million) in the close season transfer window.
In August, French newspaper L'Equipe reported that Lyon had put the majority of their squad on the transfer market to raise 75 million euros to balance their budget and meet financial sales targets. The claims in the report were denied by Textor.