Ibrahimovic opened the scoring with a powerful header into the top corner in the sixth minute, before his clever backheel set up Ezequiel Lavezzi for the second goal 13 minutes later.
The Sweden international set up Lavezzi again for the third goal two minutes from time.
The result put PSG, who take a 4-0 lead into the return leg of their Champions League last 16 tie against Bayer Leverkusen at the Parc des Princes on Wednesday, on 67 points from 28 games.
Second-placed Monaco host second-bottom Sochaux later on Saturday (1900GMT).
It did not prevent the visitors from virtually wrapping up the points in the opening 20 minutes.
Following a fine one-two with Lucas, Ibrahimovic beat Yannick Cahuzac in the air to head home from the Brazil forward's cross.
The Swede was at it again when his backheel in midfield split the Bastia defence, leaving Lavezzi free to run through on goal unchallenged and beat Jean-Louis Leca from close range.
Lavezzi then converted an easy chance after collecting Ibrahimovic's knock down and finding the net after a defensive blunder from Sebastien Squillaci.
On Friday, Olympique Marseille's Champions League challenge suffered a setback when they lost 1-0 at home against Nice to stay fifth, six points adrift of third-placed Lille.
Second-placed Monaco later beat second-bottom Sochaux 2-1.
Dimitar Berbatov put the hosts in front after six minutes, tapping in at the far post from Layvin Kurzawa's cross.
James Rodriguez made it 2-0 from the penalty spot after Berbatov was brought down 10 minutes into the second half.
Edouard Butin scored a consolation goal in the 84th, just before Jordan Ayew was sent off for kicking Andre Raggi on the leg.
Bastia 0 - 3 Paris Saint Germain
Guingamp 0 - 1 Evian
Monaco 2 - 1 Sochaux
Nantes 2 - 2 Ajaccio
Toulouse 3 - 2 Reims
Valenciennes 2 - 1 Rennes
- Sports & Recreation
- Ezequiel Lavezzi
- Bayer Leverkusen