A Guardian investigation has found workers in France’s champagne industry are being underpaid and forced to sleep on the streets and steal food to stave off hunger.

Workers from west Africa and eastern Europe in the town of Épernay, home to the headquarters of some of the world’s most expensive champagne brands, including Moët & Chandon and Mercier, claim that they are either not being paid for their work or illegally underpaid by vineyards near the town.

The Guardian found workers in the town sleeping on the streets or in tents as the vineyards did not provide accommodation. Other workers staying in a nearby village said they had been forced to steal food from local people as they did not have anywhere to buy provisions.

Yet the champagne industry has been hit by a string of controversies related to its treatment of grape-pickers, with four workers dying from suspected sunstroke during last year’s harvest. In a case scheduled to go to court early next year, four people, including a vineyard owner, have been charged with human trafficking.