Nice had led at half-time on the Cote d'Azur thanks to a deflected strike late in the first half from their Tunisian international full-back Ali Abdi.
However, PSG were much improved in the second half following coach Luis Enrique's decision to replace Randal Kolo Muani at the interval and bring on Lee Kang-in up front.
Their equaliser came from Nuno Mendes in the 52nd minute, with Ousmane Dembele setting up the Portuguese defender for a shot from outside the box on his weaker right foot which lacked power but found the bottom corner of the net.
Dembele's return was notable after the France winger was surprisingly dropped for the midweek Champions League defeat away to Arsenal.
He tested Nice goalkeeper Marcin Bulka on several occasions and PSG had chances to take all three points, including a Marquinhos header which came back off the post.
Luis Enrique's side have won just one of their last four games in all competitions and go into the international hiatus in second place in Ligue 1, two points behind Monaco.
A win for PSG in Nice would have seen them begin the weekend where they started it, above Monaco on goal difference.
"I am especially proud of my team for the way they played in the second half," said Luis Enrique, who expressed his satisfaction with PSG's start to the season.
"I think it has been a promising start. I like what I am seeing. I think it is much better than our start to last season, but the important thing is to win the league and compete in all competitions," said the Spaniard, who chose not to criticise Kolo Muani despite taking off the France striker early on.
"I could have changed five players at half-time. In this case that was the change I decided to make."
Monaco won 2-1 away at Rennes on Saturday with goals by Thilo Kehrer and United States striker Folarin Balogun.
Lyon continue upward surge
Marseille, who were held 1-1 at home by bottom club Angers on Friday, are five points behind the leaders in third place.
Reims are fourth, behind Marseille only on goal difference, as they continued their good start to the campaign by beating struggling Montpellier 4-2.
Zimbabwe's Marshall Munetsi, Japanese international Keito Nakamura and Ivory Coast striker Oumar Diakite all scored for Reims before Teddy Teuma sealed their victory with a late penalty.
Arnaud Nordin netted twice for Montpellier, who are in the relegation zone.
Also on Sunday, Brest followed their 4-0 win away to Red Bull Salzburg in the Champions League in midweek by beating Le Havre 2-0 in Brittany.
Ludovic Ajorque and Ibrahim Salah scored for Brest in a game both sides ended with 10 men.
Liam Rosenior's Strasbourg came from behind twice to draw 2-2 at home to Will Still's unbeaten Lens in Alsace.
M'Bala Nzola and Andy Diouf were on target for Lens either side of an Abakar Sylla counter for Strasbourg, who secured a point thanks to Habib Diarra's penalty on the hour.
Lyon continued their revival in form by claiming a fourth consecutive win in all competitions with a 2-0 defeat of Nantes.
Argentinian World Cup winner Nicolas Tagliafico put Lyon ahead midway through the first half at the Groupama Stadium when he converted from a Said Benrahma assist.
Lyon then doubled their lead early in the second half as Nantes defender Nicolas Pallois turned a low Corentin Tolisso centre into his own net.
The victory for Lyon comes on the back of a 4-1 win away to Rangers in the Europa League on Thursday and is their second on the bounce in Ligue 1.
Having started the season with just one win in five, Pierre Sage's team are up to eighth, above Nantes.
