Like Dickie Bird in cricket, rugby referee Nigel Owens or football whistler Pierluigi Collina, he has long transcended his role as a pure sports official.
Although he is a top umpire — having officiated at the biggest tournaments across the globe — he is also famous for his distinctive baritone voice, often compared to legendary singer Barry White. That, combined with his heavy French accent, propensity for dance moves to the music during breaks in play, and gesticulating manner in communications with the players makes him an unmistakable presence on court.
He has Facebook fan pages set up in his honour, and last year at the ASB Classic tournament organisers fielded requests from female fans for seats directly behind his chair.
"I don't think I'm famous — but let's say people recognise me," Nouni told the Weekend Herald. "It's just funny. Usually we say a good umpire is someone we don't speak about.
That's how we recognise a good umpire. These days you have a couple of chair umpires — I'm not the only one — that are quite recognisable. But I just want to make sure I am recognised for being a good official, and not being a funny guy, with a deep voice on the chair."
Nouni makes headlines wherever he goes. At Wimbledon last year the British press ran several stories on him with the Daily Mail calling him the "Cappuccino-voiced Frenchman" while the Telegraph talked about his "honeyed tones".
A British tennis fan described his voice as "[like] drowning in a vat of chocolate, golden syrup and fine brandy", while another declared she wanted him to "umpire her life".
Even former tennis great John McEnroe conceded Nouni had a "great voice", joking that "he's an argument for smoking cigarettes if you're an umpire".
"It's always nice," Nouni says with a laugh about the reaction. "I'm not going to complain. It's just tennis. People are happy, I'm happy to make people happy. They have seen a great match, they had fun, plus if they like my voice ... well, champagne."
Whenever Nouni is working on the tour — from Birmingham to Bogota, Beijing to Brisbane — he is often stopped by fans asking him to say "Deuce" or "40-Love" in his imitable style.
"I always say 'I never do on demand'," says Nouni with a smile. "If it is a guy asking 'I say I don't do it for the guys'. It happens but I don't do it. I say I'll do a picture if you want, or an autograph but on demand is a bit strange."
Nouni is serious about his job — after more than 25 years as an umpire — but extremely relaxed away from the court.
The 41-year-old is flattered, but puzzled, by the White comparisons.
"It's an honour," says Nouni. "Who is not a fan of Barry White? Of course I am a Barry White fan. But when I am listening to Barry White I don't hear myself. People ask me can you sing a Barry White song. I say no, he's upstairs, and I've got too much respect for this guy. I'm not going to sing Barry White."
Nouni, who grew up in Perpignan in southern France, started playing tennis at the age of nine — "I followed my big brother like you do".
Five years later he was doing some officiating at small local tournaments, to earn pocket money.
His big break came when he was 16, after he won a regional contest to go to Paris and work as a line judge at the 1992 French Open. His career progressed steadily from there.
Nouni worked as a chair umpire at qualifying tournaments, before progressing to main draw events on the WTA tour, then Grand Slams.
"At the beginning you are young ... it's just fun," says Nouni. "You don't know about the exams, the badges. It demands a lot of things. You have to be seen, do a lot of tournaments, invest yourself in a lot of things."
Nouni used to do up to 28 tournaments annually (with two or three matches per day) but now works between 22 and 24 events each year.
He is a proven performer in his field, having being in charge of grand slam finals, so what makes a good umpire?
"To see the ball well — that helps a lot," Nouni says with a laugh. "But communication is the key. Even if you see the ball well, if you don't have the communication skills, it cannot work. The combination is to see the ball and communicate well. And also everything has to slide off you, you know. You [can't] take things personally, you don't have to blush if you make a mistake."
Top umpires have to make judgment calls on serves travelling up to 200km/h, as well as picking out if a blazing groundstroke has nicked the baseline.
"Your eyes get used to it, if you do it for a long time," says Nouni. "You catch the ball, you follow the ball. Your eyes get trained."
Nouni points out that umpires on the WTA tour have eye tests every year — "to make sure we are not blind" — and he has his own relaxation techniques for long matches.
"I try to relax during the breaks," says Nouni. "You cannot be totally focused for three or four hours. I like to look around, calm down."
Despite what is at stake, and the fact that tempers can fray, Nouni says it's crucial that umpires stay calm.
"You have to be under control, control yourself," says Nouni. "You can be stressed but nobody wants to see it. Players don't want to see it. If you say a call and you look stressed, maybe they don't believe you."
But what about the big matches, or the big moments, where one point can decide the fate of two players?
"You cannot think about the situation ... it is the wrong way to think about it," says Nouni.
"You cannot think about the consequences. You just know that you are doing your job, you can see the ball well, you know you can handle those matches and it's your job to do that.
"Personally, I take the positive things from the pressure; a big crowd, great players, a big occasion. You are here to enjoy. I grew up to do this kind of job. And at the end, it is just a tennis court, with two player and line umpires. That hasn't changed from when I did my first final in the local tournament."
Nouni, who is visiting Auckland for the fifth time this week after first coming here 10 years ago, is also philosophical about the times when he — or one of his on court team of line judges — gets a call wrong.
"I do miss some calls, they miss some calls," says Nouni. "But it is part of the job. But I think Hawkeye shows for everyone, even the players, that most of the time the umpires and line umpires get it right."
