1. Because they feel like it
In general, staring is not considered as rude in France as in some other places. Although French mamans will tell their children that it's rude to stare (or to point) that doesn't mean that people don't do it when they grow up.
And public transport is where the art of staring is most frequently practised, especially the Paris Metro. While Brits spend their morning commute dementedly avoiding eye contact with everyone else in the carriage, it's not unusual for French people to have a good stare if there is someone in the carriage who catches their eye.
While at first it can make foreigners feel paranoid, once you get used to it it's rather freeing – spotted a woman in a fabulous coat or a bloke who is the spitting image of Jean Dujardin? Go ahead and drink in the details.
Is that Owen Wilson and Carla Bruni walking past? Go ahead and have a good stare. Photo: AFP
2. Because you look hot today
Which brings us to the next point – casual approaches in the street or public places are not unusual in France and if someone is staring at you it may be that they have decided they like the look of you and are about to approach you and say salut mademoiselle/monsieur, ça vous dirait d'aller boire un verre à deux (hi babe, would you like to get a drink with me)?
This is not an unproblematic tradition and many women, especially younger women, report feeling harassed in the streets, but at least you know that it's not just you, it happens a lot.
3. Because you're spreading your cheese
France has a lot of strictures around eating, some of them quite obscure. So while you may think your table manners are immaculate, if a fellow dinner guest is staring at you it's possible that you've breached some French dining etiquette.
If you're eating a cheese course, the cheese should be sliced and placed on the bread, not smeared into it like you're spreading margarine. Ditto foie gras.
4. Because you haven't said hello (or goodbye) to everyone
If you're greeting a table or a roomful of people it's unfortunately not enough to give a wave in everyone's general direction and a cheery bonsoir tout le monde.
French etiquette dictates that you greet everyone formally with a hello or (in non-Covid times) a handshake or a kiss. If you're in a very informal situation with younger people you can probably get away with this, but if you've been invited to someone's house for dinner or to meet the family you will be expected to greet everyone individually.
And the same goes at the end of the evening, in fact the French even have an expression for someone who just leaves and doesn't say their goodbyes properly – filer à l'anglaise aka to make an English exit.
5. Because your children are making a noise
One of the stereotypes about the French that's at least partially true is that the children do tend to be better behaved – especially in restaurants.
So if your little cherubs are running around shrieking and hitting passers-by then expect to get a few stares. You could even get a telling-off too as some French people, especially of the older generation, are not afraid to rebuke children who are not their own.
Even on a night out you may have to keep the noise down. Photo: AFP
6. Because you're being really loud
It's not just children that can be noisy. One thing that many adult foreigners will need to do (and Americans have a particularly bad reputation for this) is lower their voices.
Sitting out on the café terrace drinking and chatting with friends is one of the greatest French experiences, but if you find yourself yelling and guffawing at each other then expect to get the odd dirty look – not everyone wants to hear your conversation and French bars in general are a lot quieter than British or American ones.
7. Because you've helped yourself from the bottle
This one depends a little on your situation, but traditional French manners dictate that if a bottle of wine is on the table, the lady should wait for a gentleman to pour for her.
The younger generation are increasingly ignoring this rule (because it is after all the 21st century) but certain people of an older generation, particularly if they are more well-off bourgeoise types, still expect the men to do the wine pouring.
Whoever you are drinking with, try not to upend the entire bottle into your glass then swig it down like it's lemonade, that will make you no friends.
8. Because you're naked in Monoprix
You may have heard that nudism is common in France and it is, but that doesn't mean that you can strip off just anywhere.
If you want to be at one with nature (and we've heard that it's very freeing) there is a time and a place. Naturist beaches are clearly signposted and there are also naturist resorts – such as the famous Cap d'Agde – where you can indeed be naked in the supermarket. Events such as naked theatre trips are also organised by recognised naturist clubs.
Being naked in public is not actually illegal in France, but disturbing public order is, so if your nudity is upsetting people around you then you could be arrested.
Naturists themselves say that the first rule of naturism is respect for other people and it's not about being confrontational over your life choices.
There's a time and a place for this sort of thing. Photo: AFP
9. Because you're not wearing a mask
A hopefully short-term one this, but face masks are now compulsory in many spaces in France – in all indoor public spaces across the country and on the street as well in the big cities.
While you will of course see some French people ignoring this rule – or wearing their mask as a chin guard or elbow protector – there are plenty of others who won't hesitate to give you a hard stare or a short sharp telling-off if you are not complying.
And if the person staring at you is a police officer then bad luck, you're about to get a €135 fine.