A man holds a pen aloft as people gather in Trafalgar Square in London on Jan. 11, 2015, in honor of the victims of the terrorist attacks in Paris. Getty Images

British department store TK Maxx withdrew a shirt from sale Wednesday after customers complained that it mocked the Charlie Hebdo massacre in Paris, a terrorist attack that claimed the lives of 11 people in January. The shirt that read "Je Suis Over It" stirred outrage online, as consumers interpreted the message as making fun of the Charlie Hebdo solidarity slogan "Je suis [I Am] Charlie."

The Charlie Hebdo massacre was the worst domestic attack France has seen in decades, and thousands of people around the world, especially in neighboring European countries like the U.K., showed their solidarity with the French people through the slogan "Je suis Charlie." The catchphrase came under considerable criticism because of some of the more provocative content the satirical weekly has produced, though most people embraced the slogan simply for its show of solidarity.

"It’s appalling that a global brand has allowed a T-shirt like this to be produced and sold in stores," Tom Young, 23, told the U.K. tabloid the Mirror. Young saw the shirt in a store in Bristol, England and was very offended by the slogan. "Even if the message did not intend to cause upset in relation to the tragic event, I am adamant it should be taken down from stores immediately," he said.

The chain, which has 280 stores across Britain, immediately withdrew the shirt and apologized to all whom it had offended. Representatives from TK Maxx and from the U.S.-based manufacturer, Reason Clothing, both said the design for the shirt predated the Charlie Hebdo attacks and was first created in May 2014. The shirt was also being sold by the online retailer ASOS, which has also withdrawn its sale and apologized to customers.

“It is never our intention to knowingly offend or cause upset to anyone, least of all those affected by the terrible tragedy in Paris in January 2015 this year," said an ASOS representative.

The attacks occurred in Jan. 7, 2015, when two masked gunmen stormed the Paris offices of Charlie Hebdo, shooting and killing 11 unarmed cartoonists and editors and wounding 11 more. The terrorists killed magazine staff over content depicting the Prophet Muhammad in a way they perceived to be offensive.