It was the match at Exeter that alerted us to the talents of Elisa Riffonneau. Coming on at half-time, the young Trailfinders and France hooker took the game by the scruff of its neck.

She made three line breaks by getting on the shoulder of a team-mate; she appeared at first receiver, once putting Carys Cox through from a double-pump pass. When she made an error, she was involved again straightaway, atoning for the error. She seemed to be everywhere.

“I played against her at U20s. She was crazy good then and she ripped us apart at Exeter,” says Maisy Allen, the Chiefs and England flanker who is helping the Red Roses to prepare for the Guinness Six Nations Grand Slam decider against France on Saturday. “She’s amazing. Her acceleration is absolutely crazy.”

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Giselle Mather, DoR at Trailfinders, will tell you Riffonneau was equally impressive in a cup game against Gloucester-Hartpury early in the season. “Absolute domination,” as she puts it.

“She’s had a couple of games where she has been that impactful,” she continues. “The thing with Elisa is she gets into positions and then uses her voice really, really well to communicate that she is there. Now I know that sounds ridiculous but being able to communicate in competition is huge. A lot of athletes don’t speak at the right time or don’t demand ball at the right time. It’s a soft skill but a hugely valuable one.

“So she works hard to get into the right positions and then demands the ball. And demands it in such a way that she gets it. And then she has the power and pace to exploit that situation.”

Carrying in an Allianz Cup tie. The student has been a revelation for Trailfinders (Prime Media Images)

In Premiership Women’s Rugby (PWR), Riffonneau has been known to shout for the ball in French. And sometimes team-mates have used French as well and she has responded immediately. “It’s one of those wonderful things when you have players from across the world in your team. They all bring their own flavour and Elisa definitely brings her own flavour,” adds Mather.

Gaëlle Mignot, now coaching France, played in England’s top flight in 2015 but Riffonneau is the first French international to play in PWR. By electing to spend a year of her politics degree at Brunel University London, the 20-year-old had to give up one of the contracts on offer to the top 32 French players.

Nevertheless, she is an integral part of the French squad that hopes to prevent England winning a sixth successive title in Bordeaux this weekend, taking her place on the bench in a team showing four changes from the side that walloped Wales 40-0 last weekend.

Riffonneau hails from Tours, gateway of the Loire Valley. Mum Sabrina is a nurse, dad Didier is the man who takes charge when there are accidents on the road. Her older sister Alicia has represented France U20 and was the catalyst for Elisa taking up the sport.

“I played rugby when I was seven years old but I was the only girl,” she explains. “I wanted to try another sport, so I stopped rugby and played handball for five years. Then I went back to rugby in high school. I was 14 years old. And after that I went to a rugby academy (at Rennes) two hours from my home, so I was young when I left my parents’ home.”

Riffonneau at a French training session run by David Ortiz, the joint head coach (Corbis/Getty Images)

Flying the nest at a young age breeds independence and toughness. It helps to explain why Riffonneau was happy to cross the Channel, to experience English rugby and a different way of life. She lives with four club team-mates, Cox, Jess Cooksey, Abi Burton and Meya Bizer, in a house 100 metres from Trailfinders’ training ground.

“The contacts here are bigger than in France,” she says. “Maybe English rugby is more contact, contact; we maul or scrum. And in France it’s not like that, it’s more run into space, find the gaps. The reason I came here was to try to play as a French player but in an English league. Find my point of difference for Trailfinders.

Friend and foe: Abby Dow, the electric England wing, is a team-mate at Trailfinders (Getty Images)

“It’s the best league at the moment, so I think French players would like to come here. But it’s different for me because I’m here for my studies too. It was an opportunity for me and I took it. But it’s difficult to come here, it’s not the same language, not the same rugby. And you can’t be on contract in France and with an English club. It’s why there are not a lot of French players here.”

She made her Test debut last year in Ireland, France winning 53-3 despite incurring a red card. She had accumulated six caps by the turn of the year, helped by a calf injury to the experienced Agathe Sochat during the first week of WXV, a competition Riffonneau marked with a try against Australia.

Her lineout throwing is her biggest work-on and Trailfinders have sometimes chosen Spanish hooker Cristina Blanco at six, with Riffonneau at two, so that the Frenchwoman can be freed up to do what she does best.

On the step up to Test rugby, she says: “There is a big gap between the French championship and international level. But it’s normal because you play the best players in each country. There is a big intensity in contact and there is not a lot of fault, the game is very fluent.”

She sat unused on the bench last year during the humdinger against England at Twickenham, so this weekend’s meeting will have extra resonance. “We love playing England because it’s always close, it’s always a pleasure to play against them. We are trying to build something for the next World Cup, a group that is a mix of experience and youth.”

Skipper Manae Feleu scores France’s fifth try during their rout of Wales last weekend (AFP/Getty Images)

It seems likely Riffonneau will return home to do a Masters at the end of the season. Mather, who updates France coach Mignot regularly with her progress, would dearly love her to stay.

“She’s a fabulous character. She’s involved, she’s fun, she gets on really well with all the other athletes from all over the world, she just adds energy and enthusiasm into the environment. And she pushes standards, she really does.”

Keep an eye on her in Saturday’s Six Nations’ finale, the Riff with the biff.

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