PSG enjoyed an easy win heading into its Champions League last-16 first leg against Bayer Leverkusen.
Ezequiel Lavezzi, whose uncle died earlier this week, opened the scoring with a predatory finish after Zlatan Ibrahimovic's free kick had been deflected into his path. In the second period the hosts added to their lead, with the Swede volleying home before a Gary Kagelmacher own goal put the home side firmly in control.
The defeat is Valenciennes' 14th of the Ligue 1 season and leaves the side in the bottom three. PSG, which gave a first start to Yohan Cabaye, started with real attacking intent and should have been two goals ahead inside the opening 10 minutes as Valenciennes struggled to contain it.
Ibrahimovic saw a flicked effort cleared off the line by Kagelmacher in the fourth minute and Nicolas Penneteau then made a fine save to deny Thiago Silva five minutes later.
With pressure beginning to build on the Valenciennes' goal, it was unsurprising that PSG's bright start paid dividends as Lavezzi plundered his fourth goal of the season in the 18th minute. An Ibrahimovic free kick squeezed through the wall and dropped at the feet of the Argentine, who calmly fired low past Penneteau from 8 yards.
The 28-year-old could have had a hat trick before the half hour, but he wasted two excellent chances, while Lucas Digne saw a low shot go just wide.
Valenciennes' only sight of goal in the first half came in the 31st minute as PSG failed to clear a left-wing cross and the ball fell to David Ducourtioux, but he dragged his shot wide.
Ibrahimovic, having been denied in the first half, got his goal five minutes into the second period after some slack defending from the visitors. Having failed to clear Digne's cross, Valenciennes allowed Jeremy Menez the chance to volley toward goal. He failed to connect properly, but the ball bounced to the Sweden international and he nonchalantly fired home his 19th league goal of the season from 12 yards.
It was 3-0 two minutes later as Kagelmacher got himself into a tangle trying to clear Menez's cross and the Uruguayan inadvertently turned the ball into his own goal.
With the game won, Blanc began to think about the first leg of PSG's UEFA Champions League tie with Bayer Leverkusen on Tuesday as Ibrahimovic, Lavezzi and Thiago Motta were all substituted and the hosts coasted to victory.