A man in France with Down syndrome may have just had one of the best birthday weekends he could have ever hoped for.

He received more than 30,000 birthday cards and postcards for his 30th birthday, after his parents posted a simple request on Facebook that went unexpectedly viral.

It all began when Manuel Parisseaux's father, Lucien, wrote a message on Facebook in early November, asking friends to help "Manu" celebrate his 30th.

"Hello everyone," he wrote. "My son Manuel will be 30 on Nov. 22. He has Down syndrome. I’m writing to ask you to take a couple minutes to send him a little card and to pass this information onto your friends so the chain doesn’t get broken.

"I thank you all for your gesture, which will make my Manu so happy."

The Calais, France family had hoped to receive around 50 cards. But within days, cards from people they didn't know began arriving from all around France, Belgium and Luxembourg. After a week, more than 300 had arrived.

Parisseaux's Facebook post gained 'Likes' so quickly that Facebook automatically blocked the page, assuming that Parisseaux was sending out spam. So his wife Jacqueline created a new page under her maiden name of Francois and asked for the appeal to continue.

The cards kept coming, arriving from every corner of the world, from Sri Lanka, the U.S., Russia and Hong Kong.

The family received so many cards from around the world, the local post office had to deliver the cards by truck each day.

Lucien Parisseaux told La Voix du Nord newspaper that the outpouring of letters has brought tears of joy to his son, while Jacqueline says their family has been delighted to see how generous so many people have chosen to be.

“We would never have imagined the impact that a simple Internet message could have in a few days," she told the newspaper, between tears.

“We are surprised by this outpouring of generosity, and by the messages of support and kindness. The world is not so indifferent after all.”