Know before you go. . .
BBritish Embassy/Consulate: (00 33 1 44 51 31 00; ukinfrance.fco.gov.uk). For passports and most other visitor services, contact the consulate at 15 rue d’Anjou (same phone number) rather than the embassy
Office du Tourisme de Paris: (00 33 1 49 52 42 63; parisinfo.com), 25 rue des Pyramides, 75001 Paris
ambulance: Dial 15
police: Dial 17
Fire (Pompiers): Dial 18
Mobile emergency services: Dial 112
phone code: from abroad dial 00 33, then omit the zero at the beginning of the 10-digit number. Most Paris numbers begin with 01; Cell phone numbers start with 06; Numbers beginning with 08 are premium rate numbers ranging from 0800 free calls to premium rate calls
time difference: +1 hour
travel times: London to Paris by Eurostar takes 2 hours 15 minutes. Flight time is approximately one hour
Local Laws and Etiquette
Formal titles (Monsieur, Madame and Mademoiselle) are much more common in French than in English when greeting.
It’s considered polite to say “bonjour” when entering a space such as a restaurant, store, or even a waiting room, and you should say “bonjour” first when asking for help, rather than using an “excusez-moi” to start. . It’s an essential part of social punctuation, like saying “please” and “thank you.”
https://www.telegraph.co.uk/travel/destinations/europe/france/paris/articles/paris-travel-guide/ An expert guide to a weekend in Paris