Manchester United were rocked by Etienne Capoue's first half opener and, although Marcus Rashford equalised after the break, Jose Mourinho's side capitulated in the closing stages of the Premier League match
With an eye on PSG's midweek Champions League tie against Benfica, Laurent Blanc chose to rotate his squad as he made seven changes to the team that beat Valenciennes 1-0 on Wednesday.
He becomes Tottenham's fifth signing of the transfer window. Andre Villas-Boas' side begins its Premier League season on Sunday, away to city rival Crystal Palace.
The day after David Beckham joined the club on a five-month deal, PSG moved provisionally three points clear of Lyon at the top of the French League table with a 4-0 win over Toulouse.
In order to complete the move, the 23-year-old, who has been capped six times, has reportedly agreed to waive any signing-on fee, which would have amounted to a considerable sum had he waited until the summer to depart.
Paris Saint Germain warmed up for the opening of their Champions League campaign with a 2-0 win over Toulouse on Friday, the big-spending team's first home victory of the season.