France's meteorological agency has issued a weather warning for Paris and the surrounding areas with storms and highs of 35 degrees Celsius expected on Tuesday as the capital hosts the Olympic Games.
The agency put in place a "yellow alert" -- the second of four levels -- as a heatwave arrives from southern France.
The alert was issued in particular because "very hot" conditions across Paris were forecast to linger overnight, with the mercury not expected to drop below 22C between Tuesday and Wednesday.
Parts of southern France were on orange alert, the third highest warning, with temperatures pushing 40C in some locations.
The yellow alert level means people should "be attentive" to the impact of heat when playing sports or engaging in other physical activity, the agency said.
The scorching heat will be keenly felt by Olympians competing in outdoor events during the afternoon in Paris and its surrounding suburbs.
Beach volleyball at the Eiffel Tower, the BMX freestyle qualifiers at Place de la Concorde, and the women's rugby sevens semi-finals at the Stade de France are all partly or fully outdoors.
In the run-up to the Games, some athletes had urged event timings to be adjusted to take into account the physical toll of competing at high temperatures and the risk of heatstroke.
