The Mediterranean Sea was up to 6 degrees Celsius warmer than usual for the time of year, hitting a record of as much as 30 C (86 F) in Spain's Balearic Sea as a heat dome trapped hot air above Europe, the country's Aemet weather forecaster said.

Paris extended a red alert for high temperatures on Tuesday, with the top of the Eiffel Tower shut, polluting traffic banned and speed restrictions in place as a searing heat wave grips Europe.

French authorities imposed precautions nationwide in anticipation of peak temperatures on Tuesday, with some areas bracing for highs of 41C in a heatwave that has gripped all of Europe.