Marks & Spencer said new trade rules in place since Britain left the European Union were delaying deliveries of some fresh food to its stores in France, where at least three branches had empty shelves today.
As of January 1, goods travelling back and forth between Britain and the EU are subject to customs and other bureaucratic hurdles that did not previously exist.
The items out of stock at three Paris branches of the retailer today included sandwiches, black rice and edamame bean salad, and turkey tortilla with curry, according to labels on the empty shelves.
In a statement issued in response to Reuters questions, M&S said: "We have prepared for changes associated with Britain leaving the EU in order to minimise disruption for customers."
"As we are transitioning to the new processes, it is taking a little longer for some of our products to reach stores, but we are working with our partners, suppliers and relevant Government agencies and local authorities to quickly improve this," it added.
Marks & Spencer ready-meals are popular in Paris because they cater for a market for fresh meals to eat on the go that is underserved in France, the country that invented haute cuisine and where sit-down lunches in restaurants are considered a national ritual.
The company and its franchise-holders operate 20 food stores in France, all but one of them in Paris, according to the company's website.
At the Marks & Spencer store in a shopping centre in the Porte Maillot district of western Paris, fresh salads were out of stock.
A sign said that because of new trade rules, "we have not been able to receive our delivery today."
Fresh salads and pasta dishes were out of stock at a second store, on Franklin Roosevelt Avenue near the Champs Elysees.
At a third branch, on Boulevard Montmartre in central Paris, shelves of ready-to-eat fresh food were empty. An employee said the supply disruption was because of "Brexit and the New Year."
A spokeswoman for Lagardere, the French firm which holds the franchise for some of the stores in France, said it was working with M&S on the supply disruptions and expected the problems to be fixed by the end of January.
M&S is scheduled to update shareholders on its Christmas trading performance on Friday.