Germany won the Olympic triathlon mixed relay on Monday. Britain took silver and the United States the bronze.
The team of Tim Hellwig, Lisa Tertsch, Lasse Luehrs and Laura Lindemann finished the course in one hour, 25 minutes and 39 seconds.
The French team, which had been tipped for gold due to the presence of the women's individual gold medallist Cassandre Beaugrand and the men's bronze medallist Leo Bergere, finsihed fourth.
It was a disappointing start to the last week of competition for the French delegation which had been basking in the success of the first week which brought a record haul of Olympic medals.
On Sunday evening, France had 12 gold medals among its trove of 44 medals which surpassed the previous high of 43 set in Beijing in 2008. French athletes have bettered their medal mark the Tokyo Olympics.
"It's brilliant for a halfway point in the Games," said David Lappartient, boss of France's national Olympic Committee.
Success
"We have Games which are enthusing people and an event that is getting people behind the France team.
"The organisation has been great and, just as importantly, the team has performed."
The triathlon mixed relay, which started at the Pont Alexandre III in central Paris, was cleared to proceed on Sunday night after health bosses and representatives from World Triathlon reviewed tests on the cleanliness of the river Seine.
Hours earlier Belgium's Olympic committee said it would withdraw its team from the mixed relay due to the illness of Claire Michel who had competed in the individual race on Wednesday morning.
The Belgian committee's statement did not elaborate on the 35-year-old's illness.
Quality concerns
Leading up to the individual triathlon events, poor water quality forced organisers to cancel the swimming portion of two test runs meant to allow athletes to familiarise themselves with the course and also to delay the men's race by a day.
Test swims in the Seine scheduled for Saturday and Sunday before the triathlon mixed relay were also cancelled because of bacteria levels in the water.
“We hope that lessons will be learned for future triathlon competitions at the Olympic Games," said the Belgian Olympic Committee in a statement.
"We are thinking here of the guarantee of training days, competition days and the competition format, which must be clarified in advance and ensure that there is no uncertainty for the athletes, entourage and supporters.”
American triathlete Taylor Spivey said the uncertainty had been difficult.
"Everyone watching can see what an incredible venue this was for the triathlon with the backdrop of the Eiffel Tower and the Champs-Elysées.
“But the constant question of the water quality was very stressful for the athletes, I would say, because the contingency plan was only to push the race back, not necessarily like a plan B location.”
Marathon swimming events are set to be held in the Seine on Thursday and Friday.
Five of the eight swimmers in the men’s 1500-metre freestyle were listed to be entered in the 10-kilometre marathon swim.
Bronze medalist Daniel Wiffen of Ireland, who won gold in the 800m freestyle, said he would not train in the Seine.
“I don’t want to try to deal with any illness,” added the 23-year-old.
