Could you be thinking of Foot 2 Rue, aka Street Football?
Foot 2 Rue takes place in Port-Marie, a thinly-veiled representation of Marseille. The kids of Port Marie organize a Street Football World Cup with the help of a former professional footballer, thus attracting players from all around the world and becoming famous worldwide in the process. The sport itself consists of a stripped down version of soccer, meant to be accessible to all children regardless of money and social status and in any location.
Supposedly, the Canadian team are terrible cheaters.
It was followed by a sequel series, Foot 2 Rue Extreme which was done in 3d animation.
Tag, ancien joueur de foot de rue, devient le demi-frère de Samy, un passionné de foot de rue extrême et capitaine de sa propre équipe, la Team, dont Tag devient le coach. La Team participe à un tournoi où différentes équipes, nommées les Ninjaz, les Deltoro, les Magics, les Darksides et la Team, s'affrontent pour décider laquelle représentera la ville à un tournoi contre les équipes de tout le pays.
Tag, a former street football player, becomes the half-brother of Samy, an extreme street football enthusiast and captain of his own team, the Team, of which Tag becomes the coach. The Team participates in a tournament where different teams, named Ninjaz, Deltoro, Magics, Darksides and Team, compete to decide which will represent the city in a tournament against teams from across the country.
The IMDB summary for the English version, Extreme Football, mentions that The Dark Sides are prone to cheating.
Extreme Football is an urban spin off of traditional five-a-side incorporating elements of free running and acrobatics. Created by and for children, as soon as Samy discovers it he is determined to captain a team. He sets about recruiting his closest friend Greg and Mediterranean girl Ines as defenders, quick-witted Luna as the star striker and hyperactive Joey as goalkeeper. Together they form The Team. Competing in a shopping mall still under construction, rivalries are based on players' dedication to creativity, craft and skill. The Team's sworn enemies are The Dark Sides, who use dirty tactics - provocation, trickery and hoaxes. Trained by Samy's stepbrother Tag, can The Team win with style?
Not matching, the main team wears blue uniforms in both iterations of the cartoon.