Junior William Joyant, from Haiti to the Riviera: the entrepreneur mapping the party scene

At 24, the founder of Teufy and Oneera holds stakes valued at between €2.5 million and €4 million. Profile of an entrepreneur in a hurry, between Cannes clubs, Monaco villas and geolocation apps.

This summer, in clubs in Cannes, Oneera’s first users opened their phones to find a map of the venue, their friends' locations and the busiest areas. Behind the app is a company registered in May 2026 by Junior William Joyant, a 24-year-old entrepreneur based in Nice, who owns 70% of its capital. It is his second start-up, after Teufy, and one of four businesses he is running at once.

From Haiti to the French Riviera

His story begins far from the Riviera. Born in Haiti in 2002, Junior William Joyant was adopted at the age of four and came to France that same year. He grew up in Clermont-Ferrand, far from the sea and the yachts, then moved to the French Riviera on his own at 19, with no network and no safety net.

He cut his teeth on the ground. He worked for Taxi Nice Riviera, then Riva Boat Services in Saint-Tropez, before running VIP operations, backstage and guest reception at major Cannes nightlife venues. That is where he saw what lies behind the scenes: visitor flows, access control, security, staff to coordinate amid the noise and the crowd. Very practical problems he would later set out to solve.

At the same time, he studied. He holds a master’s degree in cybersecurity and is now studying for a master’s in event management. The dual profile may seem unusual, but it matches his businesses exactly, where technology serves first and foremost the organisation of events and the welcoming of the public.

Teufy, then Oneera: mapping the party

His first project was born in 2021. Teufy is a going-out app listing nearby parties, festivals and deals while giving venues more visibility. It has brought together more than 200 partners across the French Riviera and the Var. Junior William Joyant still owns 80% of it and plans to overhaul it completely by 2027-2028.

Oneera goes further. The idea is to lay a digital layer over venues open to the public. Visitors find their way and locate friends from their phone; organisers track crowd density, receive incident reports and coordinate staff from a dashboard. The app relies on GPS outdoors and on Bluetooth Low Energy beacons indoors.

The Cannes trials also showed the limits of the exercise: crowds, walls and constant movement make indoor positioning difficult, a challenge the whole industry knows well. Several hundred thousand euros have already gone into development. After clubs, the young company is targeting festivals, large entertainment venues, sporting events and tourist sites.

From Monaco to Saint-Tropez, the agencies

The entrepreneur also holds majority stakes in two agencies that he actively helps run. The first, launched in 2022 and 90% owned, builds mobile apps, web platforms and business software for companies and institutions, with a speciality in cybersecurity. The second, based in Monaco since 2023 and 70% owned, organises private receptions, villa and yacht parties from Monaco to Saint-Tropez, notably around the Grand Prix and the Cannes Film Festival. Their names remain confidential, as do those of their clients.

The Monaco agency handles everything, from theme to service. For a Christmas in a villa, clients asked it to recreate the world of the film The Polar Express: sets inspired by the film, a re-creation of its famous dance and waiters in costume. Decoration, staging, lighting, music, choice of suppliers, transport, reception and security are coordinated by the same team, with the discretion its clientele demands.

A fortune of €2.5 million to €4 million

It all adds up to a great deal for an entrepreneur of his age. Junior William Joyant owns 80% of Teufy, 90% of the IT agency, 70% of the Monaco agency and 70% of Oneera. His stakes are valued at between €2.5 million and €4 million, a figure that reflects the valuation of his companies and the buyout offers received for some of them. He also invests part of his income in major international companies and digital assets.

One question these figures cannot settle remains: what is a young company really worth? A valuation is not money in the bank. It rests on offers and prospects, not on accumulated profits. It can rise quickly, and melt just as quickly at the first downturn in a nightlife market known for its volatility, dependent on seasons, local authority permits and fashions.

The price of the pace

There is also the man behind the companies. Four businesses, two degrees, some fifteen companies advised: at 24, the schedule is dizzying. Is this exceptional ambition, or a race for success whose cost is hard to gauge? In a world that celebrates those who never stop, the question of staying power arises: how long can anyone keep up such a pace without losing part of themselves?

Luck has no doubt played its part. Knowing the backstage of Cannes venues from the inside and mixing early with the Riviera’s wealthy clientele opens doors that others take years to push. Yet nothing was handed to him: arriving alone at 19, with no ties on the Riviera, he had to open them himself. The merit lies in having walked through them. The challenge will be to prove that success does not rest on a contact book alone.

What comes next

Junior William Joyant does not limit himself to his own projects. He has already advised some fifteen companies on their structure, their events or their fundraising, and intends to invest in other young businesses. He is preparing to open part of Oneera’s capital, between 20% and 30%, to investors without losing control.

The coming months will be devoted to positioning accuracy, new versions of Oneera and rolling it out to new venues, ahead of Teufy’s overhaul. Above all, they will show whether this entrepreneur in a hurry can turn a string of bets into a lasting business.

Topics : Junior William Joyant, Oneera, Teufy