The victory on Sunday was PSG's third straight game wins with four goals, and they were still competing for league title with three points behind leaders Monaco, reports Xinhua news agency.
PSG's best chance in the first half appeared in the 18th minute, but Cavani just found his header hitting the crossbar.
However, PSG were not affected by a lacklustre performance in the first half. South American attacking duo Cavani and Angel Di Maria began to snatch their own chances for the goal.
Cavani released Di Maria in space in the middle with a fine pass, before the Argentine lifted the ball past Guingamp goalkeeper in the 56th minute.
Four minutes later, Cavani collected Adrien Rabiot's pass and earned the hosts a 2-0 lead.
Cavani continued his spotlight performance in the 71st minute, as he received a long aerial ball from Di Maria, and ran into the box to put the ball into the bottom-left corner, his 29th league goal, and 42nd in all competitions of the season.
Skipper Blaise Matuidi set it at 4-0 with his stoppage-time shot on target.
"At half-time, we discussed how to improve things, to better use the space left by our opponents and get more bodies into the opposition penalty box," PSG chief coach Unai Emery told the capital club's website.
"The first goal was the key. It saw us grow in confidence. In the second half, the team did the job. After the Monaco and Nice had won, it was important to win tonight."
In Sunday's other matches, Toulouse recorded a goalless draw with Marseille, and Saint-Etienne drew 1-1 with Nantes.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
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