Paris Saint-Germain forward Kylian Mbappe scored twice to help the Ligue 1 leaders beat Metz 3-1 at the Parc des Princes on Wednesday and close out the year on a high as they maintained their five-point advantage at the top of the table.

An uneventful first half ended goalless and lacked quality chances for either side, although the Parisians avoided conceding an own goal when a header by defender Danilo Pereira bounced off the post.

Vitinha put the hosts in front early into the second half, scoring with his first touch, before Mbappe doubled the lead on the hour mark with a stunning shot from the edge of the box as the France forward celebrated his 25th birthday.

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Late in the game, Kylian Mbappe's 16-year-old brother Ethan came on to make his senior-team debut for the Parisians.

Ethan Mbappe is as a technically gifted left-footed midfielder and came on to the field with their proud parents in the stands at Parc des Princes. He had been an unused substitute earlier this season against Nice.

He played for the same youth team as his brother Kylian -- AS Bondy -- and turns 17 on Dec. 29.

Metz captain Matthieu Udol pulled one back with a towering header following a corner, as the ball went in off the inside of the post, before Mbappe made it 3-1 profiting on a mistake from the visitors' defence.

PSG, who sit top of the standings on 40 points from 17 games, are five points ahead of second-placed Nice and seven points above AS Monaco, in third.

The French champions next travel to Lens in Ligue 1 on Jan. 14, after facing French Cup winners Toulouse in Trophee des Champions on Jan. 3 and a cup fixture at sixth-tier side Revel four days later.