With Lionel Messi absent through injury and Neymar starting on the bench, PSG were less than fluid with 11 men, struggling to make inroads against their stubborn hosts.
Christophe Galtier’s men were forced to play the majority of the match with 10 after Ramos’ moment of madness, the Spaniard picking up two bookings in quick succession shortly before the break, the second for dissent.
Neymar then came off the bench to squander PSG’s best chance of the second half, as the perennial Ligue 1 champions failed to move five points clear of Marseille at the summit.
Visiting goalkeeper Yehvann Diouf made a strong early save from Fabian Ruiz’s curling effort, before Dion Lopy sent a volley over the crossbar at the other end.
PSG struggled for attacking inspiration in the early exchanges, but went close twice in quick succession after 33 minutes; Nordi Mukiele blazing over after Diouf had denied Kylian Mbappe at close range.
The Ligue 1 leaders were dealt an extraordinary blow 10 minutes later, with Ramos being sent off for confronting the referee less than a minute after seeing yellow for tripping Marshall Munetsi.
Gianluigi Donnarumma got down to stop Munetsi’s goal-bound effort as Reims continued to press after the break, before Neymar side-footed wide of the near post from Mbappe’s well-timed pass following his introduction.
Vitinha then curled over as Neymar’s presence energised PSG, but Oscar Garcia’s strugglers were ultimately good value for a result that lifts them back out of the relegation zone.
What does it mean? 10-man Parisians unable to extend lead
PSG came into Saturday’s match having won six successive away games in Ligue 1, their best such run since they brought up a club-record sequence of eight in April 2017.
The result means PSG failed to capitalise on Marseille’s surprise 2-1 loss to Ajaccio earlier on Saturday, and lead their rivals by just three points ahead of next week’s huge head-to-head meeting at the Parc des Princes.
Red mist descends for Ramos… again
With PSG struggling to score against a stubborn Reims defence and also being troubled on the break, cool heads were required for the visitors as half-time approached. Unfortunately for Galtier, Ramos did not get the memo.
The Real Madrid great has now collected 21 red cards in his league career (in LaLiga and Ligue 1), at least seven more than any other defender has received in the top five European leagues throughout the 21st century.
Leaders miss Messi brilliance
Although Ramos’ dismissal left PSG short, they managed just four shots – two on target – throughout the first half, the vast majority of which saw them play with the full complement.
In truth, the Parisians struggled for creativity in Messi’s absence. The Argentine has been involved in seven goals in his last five league appearances, including five assists, and there can be little doubt Mbappe and company missed his vision on Saturday.
PSG host Benfica in the Champions League on Tuesday, with the two sides currently locked together on seven points in Group H. Reims travel to Lorient in Ligue 1 next Saturday.