The term vide grenier literally means “empty attic”, and it offers a chance to get your hands on serious second-hand bargains, from clothes and shoes to toys, small electricals and just about anything else.
These sales often take place on the street or in public squares but can be held inside sports halls.
Depending on which region you happen to be in, they may also be known as foire aux puces (flea market), foire à tout (Normandy), réderie (Picardy), pucier (Dauphiné), bric-à-brac (Centre-ouest) or troc et puces.
These different names are united under the wider label of la vente au déballage (literally the unpacking sale) in legal terms.
Confusingly, they are called brocantes in Belgium, which in France is generally reserved for sales held by professionals.
Some are historic events in their own right.
The internationally famous and massive Braderie (another common term) de Lille, which takes place on the first weekend of September, can trace its origins to the early 12th century. It attracts 10,000 stallholders and up to three million visitors to the northern city every year.
It vanished from the annual calendar between 1945 and 1963, but today attracts 2,000 sellers and 80,000 visitors to each of its events.
Tens of thousands of these pop-up sales are held all over France each year and there is bound to be one coming up near you. They are part of the fabric of life in every town, village and hamlet.
They can attract buyers from far and wide who come to chiner, the French for trawling for bargains – so the trick is to get there early.
Dedicated hunters continue to look online for good deals even when the vide grenier season ends in late September.
Everyone has heard of the French national classifieds website Le Bon Coin. Ebay and Etsy, too, are popular online private sale markets, but other, more niche, sites also exist.
Anyone can sell products at a vide grenier – but no more than twice a year. More than that and sellers, in theory, risk fines and even jail for “unauthorised commerce”.
There are restrictions on what stallholders can sell: weapons and animals are banned. Most organisers insist food and drinks may only be sold by approved traders.
Beyond that, the usual array of household items, such as clothing, books, dishes, toys, CDs and DVDs, and furniture are fair game.
Otherwise, you can ask about local events at your tourist information office or mairie.
Sellers usually have to sign up in advance to take part, although some allow you to turn up on the day.
Organisers will ask for a photocopy of an identity document (for example, your passport) and personal details.
Often there will be a simple application form to complete, on which sellers will have to declare, on their honour, that they have not taken part in more than one other sale in the current year.
This is no idle administrative fancy. Organisers must have copies of all these documents for all the sellers on hand on the day of the sale in case they are requested by the police or other local officials.
Afterwards details are handed in to the local prefecture, which can carry out further checks, and even cross-reference details against previous events.
There is a small charge to hire your space – often a few euros per square metre, though sometimes there are stalls of a set size for a modest fee.
Many dealers tour the vide greniers but private individuals are only allowed to sell their own used goods – and it is less than a decade ago that people were limited to taking part in sales in their own communes.
The good news is that any profits from selling your own items as a private individual do not have to be declared for income tax.
The image here was drawn by artist Perry Taylor. For more of his work see www.perrytaylor.fr