France's ability to turn defence into attack makes them formidable opponents as England open their Six Nations campaign this weekend, says Ben Youngs.
Guy Noves' side endured a disappointing 2016 Six Nations as they finished fifth in the table, recording only two wins.
They have not won the title since 2010 and have not been in contention since the following year, when they finished second to England thanks to a better points difference than Ireland and Wales.
England edged a tight encounter in Paris last year to seal the grand slam as the boot of Owen Farrell helped secure a 31-21 victory.
Since that defeat things have looked up a little for Noves' men, though, with impressive performances in defeats to New Zealand and Australia in November, and their revival makes Youngs wary ahead of Saturday's clash at Twickenham.
"The big thing with the French is that they can almost play a game that isn't high tempo and then all of a sudden they do one offload and then the whole team suddenly just wakes up and comes to life," the scrum-half told Omnisport.
"They make one offload and then boom, everyone wants to get involved in the party.
"They have got a big physical pack, that's very much a Top 14 [trait], very physical type of rugby, and the national team has got that ability and also people like Wesley Fofana, [Virimi] Vakatawa and those guys who can do a bit of magic and then they are very dangerous to stop.
"Last year it was a real tight game, it was only won in the last five minutes, so they pose plenty of threats and in [November] they pushed New Zealand very close as well.
"They definitely look like a different French side than we have seen in the last three or four years.
"It is always a worry because you know their threats, it's great they are back to that, but with that threat everyone is wary of the French."
Ben Youngs is a Land Rover ambassador. Land Rover has a heritage in supporting rugby at all levels, from grassroots to the elite. Through its 'We Deal In Real' campaign, Land Rover continues to shine a light on the people, players and clubs at the heart and soul of the game.