Sources have told ESPN that PSG argued Chelsea were late to send the paperwork to finalize the transfer due to errors with the documents — the first document included a mistake, the second Chelsea forgot to sign and by the time the third was submitted it was too late
The LFP legal committee met on Wednesday to discuss the registration but decided against approving the loan.
PSG had hoped to bring Ziyech in on loan for the remainder of the season as a replacement for Pablo Sarabiawho left for Wolves last week.
Ziyech joined Chelsea from Ajax in the summer of 2020 in a deal worth up to €44 million but has struggled to hold down a regular first-team place under three different managers.
The 29-year-old has made just four Premier League starts this season and was set to be pushed further down the pecking order after Chelsea made several attacking signings in January.
Information from ESPN’s Julien Laurens contributed to this report.