The Rue Saint-Denis has moved on. Twenty years ago, the central Paris thoroughfare was a notorious red-light district, with sex workers of every stripe giving it their all. Now, business has largely moved online, and only a sad-looking sex shop or two marks it out from the multicultural bustle that could be any up-and-coming quarter of London, Berlin or Lisbon.

“It definitely still exists out on the streets,” says Félix Maritaud. “Imagine someone living in precarious circumstances in which they don’t have internet access – there you go. It exists, and it makes the street workers even more precarious.”

The 26-year-old actor knows what he is talking about – he has just given an outstanding performance as a Strasbourg street hustler in director Camille Vidal-Naquet’s Sauvage. In the film, Maritaud alternates between walking the streets with a rock-star smirk – and surrendering himself to moments of deep tenderness.

He arrives for our interview dolled up with old-school Rue Saint-Denis panache: three-quarter-length leather coat, dark aquamarine leather trousers, leather backpack and an awesomely lurid top with a tiger, a masked Mexican wrestler and “Paradise-Pleasure” emblazoned on it. He compares acting to prostitution in its leasing out of the body, and says that his was immediately put to work in preparation for his character Leo (who remains unnamed in the film): Vidal-Naquet got him to faux-solicit in Paris’s Stalingrad district, and take dance lessons, in which he learned how to fall.

The result is a performance of utter rawness, intensified by the film’s procession of sex scenes. Some are funny, such as the opening impromptu handjob; others are mundane or exploitative. Undergoing all this, Leo comes across almost like a modern saint, only with a giant conical buttplug by way of ordeal.

They didn’t want to “faire du chi-chi” [make a fuss] about filming the sex, because it is an ordinary part of Leo’s daily routine. “But beyond this banality, it was often an amazing experience,” says the actor. “You find yourself in this kind of intimate communication with an actor who you’ve never seen before in your life, most of whom weren’t homosexual.” (Maritaud is.)

Nevertheless, he was in a heightened state during and around the shoot – which was like an “acid trip”. At one point, when asked to act out a panic attack in the open, Maritaud found himself unable to stop crying for half an hour. “I was caught off-guard. I wasn’t even aware of myself. It was fantastic! What’s dangerous in a film is to not give yourself completely, to want to control everything.”

It all sounds pretty method, although Maritaud has had no formal acting training. A former art student, he was preparing to take up gardening as a job in Metz when he was spotted at a bar and asked to audition for Robin Campillo’s powerhouse drama about 80s Aids activism, 120 BPM. Judging by his description of why he likes gardening, there was already an actor in him ready to germinate: “I like plants a lot. They’re a really interesting form of life. Plants are in total awareness of their environment – they sense vibrations, the air, earth, the moods of people passing – they capture everything.”

Maritaud wound up playing Max, one of the firebrands from the ACT UP group always pressing for more radical action. “Examining the politicisation of the body is something I know about [from my studies]. And on top of that, I like to have fun and I’m a fag. So when Campillo saw my photo, he said: ‘He could have been in ACT UP.’ And it’s true.”

Acting seems to have flowed directly out of his own life. He says, that like Leo, he has a wanderlust that saw him leave home in the village of La Guerche-sur-l’Aubois, 175km (110 miles) south of Paris, at 15. “Let’s say I had a need for experiences I couldn’t inflict on my parents. I don’t know, pure freedom or something. Which meant anything from travelling to living on the margins, drugs … But always happily, not something grim.” He spent time in Belgium, Lille and Montpellier, but was happiest on the roadside, “when I was thumbing rides. The moment when I was alone with myself and everything was possible.”

120 BPM, Sauvage and a third feature – Yann Gonzalez’s Un Couteau Dans le Coeur (A Knife in the Heart), in which he has a supporting role as a porn actor – have made Maritaud France’s hot young actor of the moment.

He bridles at this, criticising the labelling and commodification of gay culture. There is one label, though, that he wears as a badge of pride: “Je suis pas gay, je suis un pédé. [He switches to English.] I am a faggot.” I tell him how uncomfortable I am with the term, a slur derived from pederast. But he compares it to the earlier reclamation of queer, or black people’s use of the N-word. “Society has spent its time describing me like that to put me to one side. Me, I’m empowered enough now to lift up my head and say: ‘Yes, I’m a fag.’”

Maritaud took time to recover from the making of Sauvage, saying that in its wake he developed a reflex fear of abandonment. He has a couple more roles lined up and is thinking of publishing a book of his photos, which often feature derelict places. He has been taking career advice from the redoubtable Béatrice Dalle, whom he met in a bar and later asked to be his “godmother” for a recent Césars (the French Oscars) ceremony for 2019 hopefuls (“Just because I wanted an evening out with her,” he says).

They sometimes exchange books: the last one he gave her was about angels, and she gave him a poem by Rimbaud. He says he thinks there is a biopic in development, with Dalle playing Rimbaud’s mother. Whoever gets the lead would need a very particular skill set: poetry, vagabondry, an interest in sexual revolution, a touch of the dark side. With his friend already attached, surely a ready-made Rimbaud is sitting opposite me.

Sauvage is out on 1 March, with Q&A previews from 26 February