Bonjour.

Bonjour à tous!
and dear Anglophones you will get nowhere here fast is you are not prepared to greet people - shop keepers, people you pass on the stairs, those from whom you seek information and, if you are really trying hard, whoever you are sitting up against in a cafe, restaurant or train.
Dear Brits - remember the Visa card TV advert? Two and a half hours by Eurostar capital to capital or a short expanse of Channel separate two completely different cultures. Prepare to forget your inbuilt concept of personal space - you know, the one you were born with - try not to be offended if someone walks diagonally across you in the street or blocks your path as you try to cross the road at a narrow junction because they want to chat to a group of friends. Women of Britain, Frenchmen come first and would have taken your place on the lifeboats of the Titanic without a second glance - so don't be surprised if they don't offer that elderly lady their seat on the Metro or hold open a door. La politesse is different here - so just be assertive and remember to say 'pardon'. Forget that simmering sense of injustice you feel in England when you sense that someone is being impolite. Everyone is equal here after all.
Likewise, you know already that demonstrations of affection are quite open here. Prepare to see girlfriends or mothers and daughters of all ages walking slowly along arm in arm on the narrowest of pavements, or men in suits affectionately greeting each other in public places and lovers openly devouring each other quite openly on the tube. This is Paris after all. Relax, go with it, and save your energies for the important things in life -like how to safely cross the road.