Lens presented club record signing Elye Wahi ahead of their 1-1 draw with Rennes in Ligue 1 on Sunday, while Takumi Minamino scored twice and grabbed an assist in Monaco's 3-0 win over Strasbourg.
Wahi has penned a five-year contract with last season's runner-ups as Lens agreed a fee worth up to 35 million euros ($38 million) to bring the young French striker to the Stade Bollaert-Delelis from Montpellier.
The 20-year-old scored 19 times in the top flight last term and arrives in northern France as a replacement for Belgium international Lois Openda, who moved to RB Leipzig last month.
"The signing is a strong sign of the club's ambition," said Lens sporting director Arnaud Pouille.
"He is one of French football's most promising players."
Wahi watched his new side take a third-minute lead against Rennes through Deiver Machado, but the away side equalised early in the second half courtesy of Benjamin Bourigeaud's penalty after a foul by Salis Abdul Samed.
Andy Diouf hit the bar for the hosts with a deflected effort just past the hour, but Lens had to settle for a point – their first of the season after losing 3-2 at Brest last weekend.
Monaco are the early pacesetters after they swept aside Patrick Vieira's Strasbourg in one of two games in Ligue 1 this weekend pushed back because of high temperatures.
Japan international Minamino drilled Monaco ahead from distance at the Stade Louis II and then doubled the lead with a header from Caio Henrique's cross later in the first half.
Wissam Ben Yedder added a third for the hosts after he was set up by Minamino, rounding off a second successive victory for Monaco under new coach Adi Hutter.
"It's a good start to the season," said Hutter. "We're on the right track."
France forward Ben Yedder has scored three goals in two games since being charged with rape just before the start of the new season.
Jonathan David and substitute Adam Ounas got the goals for Lille in a 2-0 victory over Nantes as they held on despite finishing the match with 10 men.
David, scorer of 24 goals last season, got his first of this campaign when he turned home the rebound from a Remy Cabella header.
Paulo Fonseca's side had Brazilian defender Alexsandro sent off on 78 minutes for bringing down Abdoul Kader Bamba as the last man.
Lille conceded a goal soon after, but it was disallowed after a VAR review for offside.
Algeria winger Ounas eventually made sure of the points for the home side deep into stoppage time.
Brest are level on six points with Monaco at the top after their 2-1 win at promoted Le Havre, while Reims beat Clermont 2-0 and Lorient drew 1-1 with Nice.