So what is it and how did it start?
Back in the year 1997, Frenchman Atanse Périfan had the misfortune of learning that an elderly neighbour had died inside his apartment block in the 17th arrondissesment of Paris - and nobody noticed for months.
He saw the bigger picture, realizing that there wasn't nearly enough neighbourly love going on in his life.
In a bid to rectify this, in 1999 Périfan invented Fête des Voisins and urged everyone living in his block of flats to come out for a drink and a snack on that day.
The following year he took the idea nationwide and since then it's spread beyond France's borders.
Last year some 25 million people took part world wide including eight million across France.
The event's official international website says the celebration marks "the opportunity to reconnect with the values of solidarity, brotherhood and friendship that should be at the forefront of neighborly relations".
(French President Francois Hollande meets with the founder, Périfan. Photo: AFP)
So what are we expected to do?
Basically, each resident in an apartment block or on a local street is invited to make "a simple gesture" on Friday, to invite their neighbours for a lunch or a dinner - anything that will allow an opportunity to interact with each other.
In big apartment blocks in cities neighbours usually descend with a few bottles of wine of beer to share their daily apéro in the courtyard.
All city or social housing organizations are welcome to participate in proceedings.
If you're invited to one, remember the message is of solidarity and togetherness, so perhaps bring some crackers and cheese.
If you've not been invited to anything, there's nothing stopping you from knocking on your neighbours door and saying hello. You could even invite them for a beer or a coffee. Anything goes really, just be friendly.
So what are you waiting for? Go out and say hello.
There's plenty more information here (in French).