1 – NO AC. Since Paris is a very old city – and these building were built before AC was common – Do not expect your rental apartment or room to have this. If you come during the summertime – be prepared for this inconvenience.
2- Elevators and escalators are not common in public places & buildings. There is no law that requires handicap access, so when you are in the Metro – these stations are old – expect stairs.
3- Expecting everyone to speak English –this is considered a HUGE insult to the French people – you should never just walk up to someone, and start speaking English. You should always try to say a few words in French. If you really need help – with a long conversation (1 min or longer), look for a young French person – they normally speak English, and like to practice it when they can.
have fun 🙂