It tells the story of Guy (Guy A. Lepage) and his longtime girlfriend Sylvie (Sylvie Léonard), a couple in their late 30s (and as the series progressed, early 40s) living together. Most episodes would feature three segments revolving around a specific location or activity (in bed, at the restaurant, having friends over, going on vacation, etc.), sometimes telling a linear story throughout the segment and sometimes having it being random skits revolving around the setup. The show is a comedy, based around the clashing personalities of Guy and Sylvie. Guy tends to be more rational and educated, but is prone to being callous and haughty while Sylvie tends to be more emphatic and social, but can also be naive (if not outright ditsy) and emotional. Adding to the show's humor and drama are that Guy can have a bit of a womanizing side, while Sylvie is extremely possessive and suspicious of any lack of faithfulness from her boyfriend. Alongside this, Sylvie's mother and Guy have a profound dislike for one another, with Guy unable to repress his dislike of Sylvie's mother to her face, while Sylvie's mother actively tries to turn her daughter against Guy. On the flip side, Sylvie equally hates Guy's co-worker Genevieve, constantly suspecting her of trying to seduce Guy. A big stylistic choice is that the camera focuses heavily on Guy and Sylvie, to the point where several key supporting characters' faces aren't seen, sometimes being the camera's point of view.
The series was a huge success, spawning more than 30 adaptations for other markets, including an American adaptation, Lovebites and a French adaptation, also titled Un gars, une fille, starring Jean Dujardin and Alexandra Lamy. Some adaptations became quite popular in their own countries, the latter included.
This show provides examples of:
- As Himself: Yvon Deschamps, Charles Tisseyre, David Pelletier and Jamie Salé, among others.
- And the Adventure Continues: Un p'tit gars, une p'tite fille.
- Berserk Button: For Guy, it's the idea of spending time with his mother-in-law. For Sylvie, it's a jealous rage over Guy's business partner Genevieve.
- Casting Gag: Most of Guy's old friends are played by members of "Rock et Belles Oreilles", a comedy troupe which Guy A. Lepage was a part of.
- Clingy Jealous Girl: Sylvie is ridiculously insecure in her relationship and takes offense to Guy's business partner Genevieve, or to any attractive female friend Guy may have, and sometimes even cooks up schemes to try and test Guy's fidelity.
- Cute Kitten: Sylvie eventually gets one.
- The Faceless: Sort of a common gag, a large number of characters would never have their faces shown.
- The Immodest Orgasm: Sylvie got loud enough for one of their lodger to complain.
- Intra-Franchise Crossover: With its French-from-France adaptation during a trip to Paris.
- Lantern Jaw of Justice: Being played by Guy A. Lepage, Guy sports one.
- Mathematician's Answer: When Guy asks Sylvie which of two wines she wants for supper. She answers, "Yes." This prompts him to reply "When someone gives you a choice between two things, you can't answer with yes! If you're afraid of committing to a decision, do you want me to pick for you, or do you want me to leave choices up to you?" Her answer? "Yes! Yes Yes Yes!"
- MayDecember Romance: Guy's father is over 60, and his last flame, stripper Mélanie, is in her mid-20s. They have a child together, too.
- Mistaken for Gay: Sylvie's friend Daniel, who doesn't like hockey, computers, action movies or cars, but loves all his girlfriend Loulou's girly activities, leading Guy to call him gay often. Daniel is oblivious to the insult and takes it as a "guy joke".
- Obnoxious In-Laws: Sylvie's mother is pretty much Guy's Arch-Enemy.
- Old Friend, New Gender: Happens when Guy meets an attractive woman at a gay pride parade who claims to have known him in high school. Guy is initially confused until the woman reveals she's a trans woman and Guy knew her back when she presented as male, when they played together on the hockey team.
- Running Gag: A large number, including the destruction of blue teddy bears resembling Sylvie's childhood one, as well as the "Road Runner". The latter consists of Guy saying "Road Runner!" and then grabbing Sylvie's chest while saying "Beep-Beep!"
- Small Name, Big Ego: After Sylvie made a few television talk show appearances, she began acting like she was a big movie star.