Argentine skipper Lionel Messi came on as a second-half substitute to make his PSG debut in a Ligue 1 against Stade de Reims on Sunday.
Messi, who joined PSG from Barcelona on a two-year contract earlier this month, replaced Brazil striker Neymar in the 66th minute.
Mbappe broke the deadlock in the 14th minute off a header to put the Ligue 1 giants 1-0 ahead
And in the 63rd minute the Frenchman got his double by getting on the end of a pin-point cross from Hakimi on the counter.
PSG have now won all four of their opening league games and top the table on 12 points.