When the multi-billionaire Arnault family, owners of the Louis Vuitton (LVMH) luxury group, acquired Paris FC in 2024 their stated ambition was to get the club promoted to Ligue 1.
Now, after a year of acclimatisation to life in the top flight, they have turned to Rosenior as they bid to take the next step and eventually challenge city rivals Paris Saint-Germain's stranglehold on the domestic game.
Qatar-backed PSG have long stood unchallenged in Paris, with the 2025/26 Ligue 1 season the first in 35 years to feature two clubs from the French capital.
But the longevity of that situation looked in doubt as PFC flirted with the relegation zone over winter and coach Stephane Gilli was shown the door despite having overseen their long-awaited return to the top division just a few months prior.
To ensure the Arnaults' best-laid plans would not go astray so early in the project, they turned to veteran coach Antoine Kombouare, who calmly guided PFC to an 11th-place finish.
But with no agreement reached on the terms of a contract extension, Kombouare left as abruptly as he had arrived.
With that chapter closed, PFC have set off down a new path by turning to 42-year-old Rosenior, with the aim of leading the club "step by step" towards the top of the Ligue 1 table, explained sporting director Marco Neppe.
"It's important for us not to rush things," Neppe said. "What's important is that we don't set ourselves any limits, we want to keep growing."
The German's words echo the vision of owner Antoine Arnault, the son of France's richest person and LVMH CEO Bernard Arnault.
When the family, along with minority stakeholders Red Bull, announced the takeover of the then second-division PFC in November 2024, Antoine Arnault insisted that there would be no shortcuts to success.
"We're not here to change everything, or to flip the table," he said. "That's very important, because in football there are no magic solutions."
But since those words, PFC gained promotion at the first time of asking and after finishing just outside the top half of the Ligue 1 table last season, they now have their eyes on loftier goals.
If Neppe would only insist that the club's sole stated objective is "to do better" than last season's 11th-place finish, the hiring of Rosenior would suggest they have European football in their sights.
'Big potential'
Rosenior made his name in Ligue 1 between 2024 and January 2026 as he oversaw Strasbourg's return to European football, but his move to Stamford Bridge turned into a fiasco, with him being sacked in April after 23 matches.
His final five Premier League matches all ended in defeat without Chelsea managing even to get on the scoresheet - an unwanted first since 1912 which left Rosenior's reputation in his homeland in tatters.
But PFC are confident the 42-year-old is the man to "make the next step", even if Neppe refused to be drawn on what exactly that should be.
"I feel like myself and the staff have joined such an exciting project, where the potential is so big," Rosenior said at his unveiling in July.
"The reason I'm here is that we have a strong idea in the way that we play in our game philosophy."
Rosenior insisted that if his time at Chelsea was a disappointment, he had nonetheless learned "many lessons" that would set him in good stead to succeed back across the Channel.
"Those lessons that I take away from Chelsea, we will put into this job and hopefully we'll help this club be a very, very big club in world football as well," he said.