Jeremy Menez scored the only goal of the game in the second half to send PSG seven points clear of second-placed Marseille with two games to spare.
It is the club's first title since Qatar Investment Authority bought the club with around £250million spent assembling a squad for Carlo Ancelotti.
PSG's title will not, however, be confirmed until a league disciplinary panel meets to decide whether to impose a points deduction following allegations sporting director Leonardo barged a referee.
The Brazilian will front a hearing before the end of the season after he was charged for an incident that took place in the tunnel after PSG's 1-1 draw with Valenciennes at the Parc des Princes last weekend.
Third-placed Lyon were looking to cement their spot for next season's Champions League and began brightly with Nicolas Douchez called into action to keep out Bafetimbi Gomis' volley.
His counterpart Anthony Lopes produced his own smart stop moments later to prevent Zlatan Ibrahimovic scoring his 31st goal of the season.
Both teams were going for the jugular at the Stade de Gerland and after 11 minutes Arnold Mvemba released Yassine Benzia
and his powerful 30-yard effort was cleared away by Douchez, who less than 60 seconds later, kept out Clement Grenier 's free-kick.
Lopes repelled a Menez effort two minutes later, but moments later Thiago Motta won the ball, played a one-two with Ibrahimovic before sliding the ball to Menez who angled a shot across the keeper and into the corner for his fifth league goal of the season.
With the goal they needed, PSG played on the counter and Javier Pastore's 65th-minute effort which was saved again by Lopes the only other action of note.
The final whistle sounded and Ancelotti and his staff joined the players on the pitch as the Italian secured his third domestic title, while star man Ibrahimovic his 10th.