He has won five US National titles and the World Scrabble Championship three times.
Ms Fagerlund, the former president of the New Zealand Scrabble Association, said Mr Richards also won the King's Cup - a very popular tournament in Thailand - for the 11th time just a few weeks ago.
She said the French players would have been aware of his Scrabble-playing ability.
"He does have a reputation for being the best Scrabble player ever and they know about him already, but they probably didn't necessarily expect him to go in for the first time and beat them at their own game."
In 2008, Mr Richards won the World Players Scrabble Championship in a three-day tournament in Dallas.
The Christchurch engineer had also won the United States' 2008 national championship and its US$25,000 ($45,000) prize in Florida in July that year.
President of the Christchurch Scrabble club Shirley Hol said the French win was "quite remarkable".
She was told about his victory on Monday and said from what she had heard the French were quite "gobsmacked".
"I think one of the comments was 'Are you extra-terrestrial or something?' Because it was so amazing."
Ms Hol had played with Mr Richards in Christchurch and said he was a very talented Scrabble player.
"Initially he was just average, but he grew very quickly - obviously had a flair for words."