The four deaths were reported from Rheims and Châlons-en-Champagne, two cities in northeastern France, in recent days as temperatures soared to 34C (93F) in the region at the end of last week.

Grapes for champagne are grown on 34 hectares in eastern France, where over 16,000 growers produce over 300 million bottles of champagne each year.

France's Champagne region has seen one of its wettest June-July periods in the past half-century, and that excess rain is causing problems for its winemakers.

France is set to revise its official Champagne area to reflect the changing climate, allowing dozens of extra communes to use the strictly protected label for their sparkling wines.

Chardonnay, pinot noir and meunier grapes blanket the rolling hills and deep valleys of Champagne, which covers more than 130 square miles, from the city of Reims to the Aube river. The area is ...