Ibrahimovic opened his account for 2013 with the game's decisive strike two minutes before half-time at Stade Chaban-Delmas as Carlo Ancelotti's side handed Bordeaux a first home loss of the season.
PSG had ceded first place to Lyon following a disappointing goalless draw against Ajaccio last weekend, but Sunday's victory saw the capital club usurp Remi Garde's outfit on goal difference with both teams locked on 42 points.
Defeat for Bordeaux snapped a six-game unbeaten run, leaving them in seventh place, 10 points off the pace.
A minute's silence was held prior to kick-off in honour of PSG's British performance director Nick Broad, who died Friday after he was involved in a car accident just outside the French capital.
The highlight of a dour opening half an hour saw referee Stephane Lannoy replaced by fourth official Benoit Bastien after succumbing to a thigh injury before Ibrahimovic finally drew a comfortable low save out of Cedric Carrasso from a long-range free-kick on 34 minutes.
Salvatore Sirigu then turned away a fizzing drive from Ludovic Obraniak, who returned to action for Bordeaux following two months out with an ankle problem, while a speculative strike from Fahid Ben Khalfallah was straight at the PSG goalkeeper.
Bordeaux appeared the more threatening side as they grew in confidence, but Francis Gillot's men came unstuck on 43 minutes as Brazilian starlet Lucas Moura supplied his first assist since arriving from Sao Paulo.
The highly-rated Moura played in Ibrahimovic on the right, and the Swedish striker fired under the body of Carrasso from an acute angle to extend his league-leading goals tally.
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Clear-cut opportunities were again at a premium after the interval with Carrasso preventing PSG from adding to their lead as he thwarted Maxwell from close range after the full-back had advanced down the left side of the penalty area.
Henri Saivet came closest to salvaging a point for Bordeaux eight minutes from the end but his strike from distance was tipped over by Sirigu to preserve a 14th clean sheet of the season for the Italian.