"Les Parisiens" are seeking to win the French title for the first time since 1994, having been runner-up last season.
The club's owners, the Qatar Investment Authority, have splashed out on top players such as Zlatan Ibrahimovic, Thiago Silva, Javier Pastore and Lucas Moura since taking over in 2011.
Carlo Ancelotti's team tops the Ligue 1 table on goal difference after 22 of 38 rounds in the 2012-13 campaign, and will play in the knockout phase of Europe's top club competition in a two-legged tie against Spanish club Valencia on February 12 and March 6.
Former AC Milan coach Ancelotti managed Beckham during the former England captain's first loan spell with the Serie A club in 2009.
However, Beckham might be struggling to be fit for those matches, according to the manager of English club Arsenal -- who allowed the veteran to train with his squad this month.
"He told me that he doesn't look at all to be in shape. Beckham is super-ambitious," Arsene Wenger told reporters this week.
"If, in his mind, he wanted to play in the Premier League he would not have gone on holiday. He would have prepared and come in and tried to impress me. He told me he has done nothing at all."
Beckham admitted it might take "a few weeks" to get fully fit.
"It won't take long," he said.
He explained that he could not play for another club in England except Manchester United, where he won six Premier League titles and the Champions League before moving to Spain in 2003.
"It's the team I support and the team I dreamed of playing for," said Beckham, who to Manchester as a teenager and progressed through the club's academy.
"I'm very honored by the offers I had from other Premier League clubs but I didn't want to play there unless it was for Manchester United."