Alidu Seidu, Nice and the Joker Rule: How Ligue 1 Lets Clubs Sign Players After the Window

Every September, the transfer window closes and football convinces itself the market is over. Managers hold press conferences about the squad they have built. Clubs release statements about being satisfied with their business. But, somehow, French football keeps signing players anyway, and nobody bats an eye, because French football has a rule that says it can.

OGC Nice are bringing in Alidu Seidu on loan from Rennes until the end of the season, days after the summer window officially closed. Antoine Mendy tore his ACL before the season started, Nice needed cover at right-back, and rather than panic, they went to their list and found what they needed, already playing in France, available, and familiar with the league.

What makes it possible is a rule that most fans outside France have probably never heard of.

The Joker Rule

The LFP, which runs Ligue 1 and Ligue 2, gives each club one additional signing slot per season (that is, outside the transfer window). This extra slot opens after the summer window shuts and stays open until January. The French call it the joker unique, the single joker, and clubs guard it carefully, because they only get one.

The player must already hold a contract with another French club. For example, you cannot reach into Spain or Germany for a solution. You cannot sign someone who has been sitting without a club since June. The target has to be playing in France, contracted, and available because his club agrees to release him. That last part is where French football does something genuinely unusual: it has no release clauses. No French club carries a legal obligation to accept any offer, no matter how large. A joker transfer only moves when both clubs really want it to happen.

In practice, this is the kind of player that changes clubs through a joker deal is a first-choice star angling for a bigger move. More often a player squeezed out of his starting spot, or a club happy to clear a wage while keeping a sell-on option, or simply a situation like this one at Nice, where a specific position opened suddenly and one French club had the solution the other needed.

Seidu did not make Rennes’ squad for the first four league games this season, and competition at right-back has him down the pecking order. A loan to Nice suits him well before Ghana’s AFCON qualifiers in October. Rennes removed a wage, Nice fill their gap, that is how the joker works.

The Medical Joker

Reports around Mendy’s injury initially floated the idea of a medical joker. Nice ruled that out fast, and the reason explains something important about how French football structures its emergency mechanisms.

A club can only trigger it in three situations. Under Article 213 of the LFP Administrative Regulations, it can only be applied where a player in the club’s books dies, a goalkeeper suffers a serious injury, or a player picks up an injury while on a France international call-up that rules him out for at least three months, having already made five senior appearances for France.

Mendy tore his ACL in pre-season, not during a France camp. The medical joker does not apply, full stop.

Also, the medical joker requires the signing to be a free agent, whereas the regular joker demands the opposite. The player must hold an active contract at a French club.

The most dramatic joker transfer in recent memory happened on September 3, 2019, the day after deadline day. Nantes lost their captain, Valentin Rongier, to Marseille for around €8 million. This was a permanent move of one of Ligue 1’s better midfielders, completed after the main window had already closed.

Since then, RC Lens used their joker in November 2022 to bring in defender Julien Le Cardinal. Monaco triggered theirs in November 2023 for Kassoum Ouattara from Amiens, patching the hole that Caio Henrique’s injury opened up.

Sporting directors across Ligue 1 do not wait for injuries to happen before they start thinking about this. They track potential joker targets throughout the summer, building shortlists of contracted players who might become available if a need emerges. When Mendy’s ACL came back confirmed, Nice already had names. Seidu was the best fit. That preparation is what the LFP designed the rule to encourage.

The Premier League revisits the idea every autumn, usually after an English club watches their early-season injury crisis crumble with no way to respond until January. They argue that clubs might deliberately delay summer decisions if there is a September joker option. That makes sense, but it also overestimates how often clubs move with that kind of patience.

Most of the time, clubs sign players when they can and patch problems when they must. The joker gives French football a sensible way to do the latter. Everything else, the clauses, the restrictions, the single-slot limit, stops it becoming a parallel market. It is only what the name says: one card, played once, when you really need it.