Lyon had dominated the top tier of women's football in France, their stranglehold on the league dating back to 2007.
PSG had finished second on eight occasions during that period, but that changed thanks to a 3-0 home win over Dijon in their final game of the season.
French capital club PSG went into the final round a point clear atop the table following their goalless draw away to rivals Lyon in the penultimate fixture.
PSG got their hands on the trophy thanks to goals from Sara Dabritz, captain Irene Paredes and Jordyn Huitema, despite Lyon's 8-0 demolition of Fleury 91.
Olivier Echouafni's PSG went through the league campaign undefeated after 22 games, winning 20 matches, while scoring 83 goals and conceding just four times.
It is not the first time PSG have snapped a Lyon streak in 2020-21.
Lyon suffered their first Division 1 Feminine loss in four years, the club's incredible streak halted by PSG in November.
The dominant force of women's football in France and Europe, Lyon's 80-match unbeaten league run – which featured 75 wins – was ended following a 1-0 loss.
Not since December 2016 had Lyon tasted league defeat.
PSG also upstaged Lyon after extra time in the Women's Champions League quarter-finals this season.
Lyon won a fifth consecutive European crown in August, beating Wolfsburg in the final, and they are unsurprisingly set to be at the forefront of FIFA's end-of-year awards ceremony.
Of the 11 players on the shortlist for The Best FIFA Women's Player, five played for Lyon last season.
Lucy Bronze - third in this category last year and second in the 2019 Ballon d'Or Feminin - has since moved on to Manchester City but makes the cut alongside a host of former team-mates.
Dzsenifer Marozsan was second in 2018, the same year she finished third for the Ballon d'Or, and will now compete against Delphine Cascarino, Saki Kumagai and Wendie Renard.
Chelsea have three contenders in Pernille Harder (signed from Wolfsburg), Ji So-yun and Sam Kerr, while Caroline Graham Hansen and Jennifer Hermoso represent Barcelona. Viviane Miedema is in for Arsenal.
Such is the depth of Lyon's squad that Ada Hegerberg - the 2018 Ballon d'Or winner, then third behind Marozsan in the FIFA voting - is not in the running this year having been out since January with a ruptured anterior cruciate ligament.
Although Lyon have continued to win regardless, their four-year, 80-game unbeaten Division 1 Feminine streak was ended by Paris Saint-Germain last week.
Sarah Bouhaddi, who conceded the only goal in that game, is up for The Best FIFA Women's Goalkeeper as the sixth Lyon player honoured.
She is up against Ann-Katrin Berger, Christiane Endler, Hedvig Lindahl, Alyssa Naeher and Ellie Roebuck.
The French giants' Jean-Luc Vasseur is among seven nominees for The Best FIFA Women's Coach after a successful first season in charge at OL.
Future England coach Sarina Wiegman, the 2017 award winner who finished second in the subsequent two years, is also in contention.
Lluis Cortes, Rita Guarino, Emma Hayes, Stephan Lerch and Hege Riise are the others under consideration.
The Norwegian landed the inaugural women's Ballon d'Or in December 2018 to reflect her status as the world's leading player, but now she faces a challenging road to recovery.
Hegerberg announced on Twitter: "So here it is. I ruptured my ACL this weekend. This is a setback for me, but I'm going to work through this with all my heart and my energy. The best is yet to come. YOU'LL SEE ME SOON!"
Lyon confirmed the blow, announcing on their website: "Lyon regret the injury to Ada Hegerberg, victim of a rupture of the anterior cruciate ligament in the right knee, that occurred in training.
"The operation date will be determined in the coming days and the unavailability will be corresponding to the known statistics for this type of injury.
"Lyon will offer Ada the best surgical conditions and post-operation rehabilitation to return her to full strength."
Lyon president Jean-Michel Aulas sent a message to 24-year-old Hegerberg, writing on Twitter: "You are very strong Ada, on and off the pitch! We're all going to work to get you back in the best condition to return even stronger.
"We'll be at your side, the Lyon women will stay at the highest level waiting for your return."
Lyon sit top of the French women's championship with 38 points from 14 games, and Hegerberg has scored 23 goals in 18 matches across all competitions this season.
She controversially missed last year's World Cup, having made herself unavailable to Norway because of her stance over how women's football is treated in her home country.
The dominant force of women's football in France and Europe, Lyon's 80-match unbeaten league run – which featured 75 wins – was ended following a 1-0 loss.
Not since December 2016 had Lyon tasted league defeat, the 14-time reigning champions upstaged by PSG 1-0 in the French capital.
PSG got the better of Lyon again at Parc des Princes, where Marie-Antoinette Katoto's 10th-minute goal settled the contest.
With the shock result, PSG moved top of the table by one point ahead of seven-time European champions and Champions League holders Lyon through nine matches.
Olle-Nicolle took charge of PSG at the end of last season following their D1 Feminine title success.
PSG are second in the table this season, needing to beat title rivals Lyon in their penultimate game on Sunday to keep their slim championship hopes alive.
But preparations for that game have been overshadowed by allegations made relating to Olle-Nicolle that, the club say, "if confirmed, would be incompatible with the sporting and human values of Paris Saint-Germain".
A statement late on Tuesday read: "Paris Saint-Germain was informed today of inappropriate behaviour and remarks to which members of its women's team have allegedly been exposed.
"These facts and statements, if confirmed, would be incompatible with the sporting and human values of Paris Saint-Germain.
"Paris Saint-Germain takes the situation very seriously and intends to shed light on the facts and remarks reported.
"In this context and in order to preserve the interests of all stakeholders, the coach of the women's team has been put on leave today, by mutual agreement with Paris Saint-Germain.
"This measure is of a precautionary and temporary nature. It does not prejudge in any way the results of the internal investigation that will be conducted, nor the decisions that the club may have to take."
Its commercial value can grow sixfold to €686million by 2033 and club sponsorship could swell to €295million by the same point, according to European football's governing body.
The developing professional leagues across Europe remain at an early stage of growth, emphasised by the fact spending on international player transfers topped €2m for the first time last year.
UEFA published its 'Business Case for Women’s Football' on Tuesday, with the women's game planning to capitalise on the success of international tournaments such as Euro 2022 by aiming to steer supporters and investors towards the clubs and leagues that in some cases are battling to survive.
The report said stakeholders have "an extraordinary opportunity to develop and professionalise women's football in Europe over the next decade by investing now" to unlock "enormous potential".
The report's findings would enable stakeholders "to make informed decisions and invest on the scale required", its authors said.
UEFA explained that previous data in this area, looking at the prospect for future growth, meant there was an "inconsistent and incomplete" picture of what the years to come might hold. It said its research and data investigations this time were "unprecedented" in their scale.
Former Germany striker Nadine Kessler, who is now UEFA's chief of women's football, hailed the game as being "on an incredibly exciting trajectory".
Kessler added: "The potential of the women's game is limitless and we believe we are on course to take women's football to heights that were unimaginable just a few years ago.
"As this report shows, now is the time to capitalise on the momentum we have created together, now is the time to get involved, now is the time to invest."
The research showed that a current fan base of 144million could reach 328million in 10 years' time. Followers were described as being broadly "diverse, progressive and young", with close to one in three fans of the women's game found to be new to football.
Lyon president Jean-Michel Aulas pointed to the prospect of short-term losses for long-term gains.
Aulas, an early advocate of the women's game, said: "In the early years, there will be losses to reach a certain level and become successful. Over time, the investment will create excellent value for the club through new partners and a differentiated fan base."
That was reflected in the report stating the "majority" of leagues and teams are making a loss, relying on support from club owners or men's team budgets to remain sustainable.
Some 87 per cent of integrated clubs said involvement with women's clubs had brought about a reputational boost.
UEFA said its research showed 70 per cent of women's clubs and 50 per cent of leagues are aiming to be self-sustainable within the next decade.
