This was Mbappe's 21st Ligue 1 goal of the season and his 33rd in all competitions in 39 games.
According to local media in Strasbourg, Leipzig are paying around 15 million euros ($17.9 million), for the defender who has played 44 times for the Alsace outfit since joining the club in July 2017. He has two France under-20 caps.
Ligue 1: Jose Fonte's late header helps Lille draw against Strasbourg; Monaco extend unbeaten run to 12 games
Lille are now two points ahead of second-placed Paris Saint-Germain, although Lyon could move within a point of the pace-setters when they visit Marseille later on Sunday.
Defending champion PSG beat Strasbourg 4-0 in an otherwise uninspired performance that saw the home side benefit from three late goals amid sloppy defending from the visitors.
Ligue 1: Lille register big win over Lens to move to top of league table; Lyon beat struggling Strasbourg
Lille are top of the French league, undefeated and with the fewest goals conceded, after beating northern rival Lens 4-0 on Sunday to move two points above defending champion Paris Saint-Germain.
Montpellier's defense kept Nice striker Kasper Dolberg quiet while veteran center half Daniel Congré took care of scoring duties with two in a 3-1 win.
Ligue 1: Eduardo Camavinga's goal propels Rennes to win over Montpellier as both teams see red; Nice beat Strasbourg
Rennes teenager Eduardo Camavinga celebrated his first France call-up with a terrific solo goal in Saturday's 2-1 victory at home to Montpellier in Ligue 1.
Ligue 1: Marseille held to 2-2 draw by struggling Amiens; Paris Saint-Germain's match vs Strasbourg postponed due to coronavirus
Marseille trails Paris Saint-Germain by 12 points, but remains favorite to qualify directly for next season's Champions League.
Ligue 1: Clinical Lyon script comeback to end Strasbourg's unbeaten home run; Montpellier climb to fourth with win over Amiens`
On a cold evening in Alsace, Lyon suffered throughout and converted its few chances. Midfielder Jeff Reine-Adelaide snatched the winner 15 minutes from time from Maxwel Cornet’s assist after the Lyon striker canceled Strasbourg’s opener.
Ligue 1: Marseille end slump with Strasbourg win; Wissam Ben Yedder strikes late to give Monaco victory over Rennes
Marseille ended a four-match winless streak in Ligue 1 on Sunday after Boubacar Kamara's early strike and a late Kevin Strootman penalty saw them to a deserved victory over lowly Strasbourg.
Ligue 1: Injury-hit Paris Saint-Germain slump to shock home defeat against Reims; Lille score victory over Strasbourg
Paris Saint-Germain fell to a shock 2-0 loss to Reims at the Parc des Princes on Wednesday as headers from Hassane Kamara and Boulaye Dia gave the visitors a famous win.
The current edition of France's League Cup will be the last as the tournament has been suspended from next year, reason being its failure to find takers for TV rights
Ligue 1: Dario Benedetto's brace helps Marseille pull off come-from-behind win over Monaco; Neymar snatches victory for PSG
Marseille are now only two points adrift of reigning champions and leaders Paris Saint-Germain, and behind Rennes and Nantes on goal difference
Ligue 1: Neymar shrugs off hostile reception from Paris Saint-Germain fans to score stunning injury-time winner against Strasbourg
Neymar shrugged off a hostile reception as he marked his return to action for Paris Saint-Germain with a stunning injury-time winner.
Ligue 1: Neymar could make Paris Saint-Germain return on Saturday against Strasbourg, says Thomas Tuchel
Neymar could return to action for Paris Saint-Germain on Saturday following four months of absence after the Brazilian was selected in the matchday squad for the Ligue 1 match against Strasbourg.
Ligue 1: PSG striker Eric Maxim Choupo-Moting apologises for missing potentially title-winning sitter against Strasbourg
Choupo-Moting gave PSG an early lead with his third Ligue 1 goal against Strasbourg on Sunday, but later in the first half somehow succeeded in turning a net-bound Christopher Nkunku shot onto the post while standing on the line
Ligue 1: PSG miss chance to wrap up title after Eric Maxim Choupo-Moting's goal-line howler against Strasbourg
Paris Saint-Germain squandered the chance to clinch the Ligue 1 title in record-equalling time on Sunday after a 2-2 draw at home to Strasbourg, with Eric Maxim Choupo-Moting's incredible miss from on the goal-line costing his team dear
Ligue 1: Skipper Marcelo injured as Lyon stumble against Strasbourg as Champions League trip to Barcelona looms
Lyon's stand-in captain Marcelo left the field with a leg injury as his side struggled to a 2-2 draw at Strasbourg on Saturday, just days away from the Champions League last 16 second leg at Barcelona.
Ligue 1: Kylian Mbappe becomes youngest ever player to score 50 French league goals as PSG cruise past Nimes
Kylian Mbappe became on Saturday the youngest ever player to score 50 Ligue 1 goals after striking twice in Paris Saint-Germain's comfortable 3-0 win over Nimes that tightened the champions' grip on the French title.
French League Cup: Lebo Mothiba's brace powers Strasbourg past Bordeaux to first major final since 2005
Lebo Mothiba scored twice as Strasbourg fought back to beat Bordeaux in the French League Cup last four to reach their first major final since 2005.