Nicolas Touzaint had to withdraw his horse Galan De Sauvagere
France's hopes of defending their Olympic eventing title appear to be over following the withdrawal of medal hope Nicolas Touzaint.
The 28-year-old was forced to withdraw minutes before he was due to compete as his horse Galan De Sauvagere was lame.
Jean Teulere had already pulled out on Thursday because of an injury to his horse Espoir de la Mare.
Britain ended day one of eventing on a high after Tina Cook scored 40.20 penalty points to finish eighth.
Cook, on Miners Frolic and competing in her first Olympics, put in an impressive performance after fellow Britons William Fox-Pitt and Daisy Dick endured a disappointing morning session.
Fox-Pitt, on Parkmore Ed, could only manage 11th with a score of 50.20 penalty points, while Dick and her mount Spring Along scored 51.70 and are two places further back.
Cook's result leaves Britain fifth in the team event heading into day two.
"I'm disappointed," said Fox-Pitt. "He is capable of a lot better. He seemed aware of where the exit was and it was hard to keep him concentrated."
Leading the field after the first event is British-born Australian rider Lucinda Fredericks who scored 30.40 on Headley Britannia.
Belguim's Karin Donckers is behind the 42-year-old in second place after accumulating an impressive 31.70 points on Gazelle De La Brasserie.
Cannot play media. Sorry, this media is not available in your territory.
Interview: GB three day eventer Daisy Dick
Australia hold a commanding lead in the team standings after Megan Jones, on Irish Jester, scored 35.70 to finish third and Clayton Fredericks, Lucinda Fredericks' husband, scored 37.00 on Ben Along Time.
The US are 18.70 points behind in second, while Germany and Sweden are third and fourth respectively.
The third session of the dressage section of eventing begins early on Sunday with Sharon Hunt and Olympic veteran Mary King the final two Team GB members to compete.
Saturday's event was briefly disrupted after pro-Tibet protesters attempted to display the Tibetan flag and chant pro-democracy slogans.
The four protesters were ejected and banned from the Hong Kong venue but escaped arrest.