During Your Stay

Early Arrival

If you plan on arriving earlier than the official check-in time (usually from 2pm), try to give your hotel as much notice as possible. If they're completely booked, it may not be possible to have a clean room ready earlier than normal. The smaller the hotel, the less likely you'll be able to go to your room right away. Most, however, will let you use a bathroom to freshen up and store your luggage so you can go out on the town.

Hate Your Room?

If you hate your room, it may be possible to change if there are others available and youask politely: "Excuse me, do you have any other rooms free, maybe with a different view/decor/bathroom?" You're being a pain in the a**, so don't forget to apologize for being difficult and thank them if they try and help you. If it's a size issue, you may have to pay for an upgrade.

If there's no way in hell you want to stay in the hotel one more minute, be sure you're aware of the cancellation policy so you don't end up paying the entire week you've reserved. If you need to find a new hotel pronto, same-day reservations can be made through the Paris Tourism Office for a fee.

Breakfast

Almost all Parisian hotels charge extra for breakfast, from €5 to more than €40 at luxury establishments. Standard continental breakfast is coffee/tea, baguette, croissant, jam, and butter, sometmes juice and yogurt. Many hotels now offer pricier buffet breakfasts with more substantial fare like cheese, cereal, fruit, meat, and eggs made to order. I usually recommend people eat breakfast outside the hotel to save money. But if there are no cafés near the hotel and you can't bear walking more than ten feet without your morning coffee, then perhaps the trade-off of convenience for price (especially for breakfast in bed) is worth considering.

Be sure the staff know whether you're going to have breakfast or not (usually the night before), or you may get a surprise on your bill. 

Earplugs

You might be in a hotel with double-glazed windows but paper-thin walls. Trying to sleep through slamming hall doors, noisy plumbing, or enthusiastic vacuuming at 8am will be a lot easier if you invest in a good pair of earplugs.

Noisy? I once asked a hotel manager of a luxury chain why they didn't provide earplugs with the rest of the bathroom amenities. He replied, "That would imply our hotel is noisy." Uh huh.

Etiquette

Having said that, don't be the noisy guests in the hotel! Especially if it's small. Everyone will know and you'll get nasty stares in the breakfast room. Don't drag your suitcase down the spiral wooden staircase at 7am, blast your TV at 2am, or forget to turn off your alarm before leaving the room for the day. And keep your voice down when walking through the halls at any time of day in case jet-lagged travelers are trying to sleep at noon.

Be sure to tip the housekeeping staff (some change on the pillows), especially if you're particularly messy. And try not to be big slobs. Some hotels have begun banning guests from bringing food up to the rooms because their "picnics" have gotten out of hand. Take out your own smelly cheese rinds and empty wine bottles when you leave the room (or at least put them in a knotted plastic bag).

Security

There is no perfectly secure hotel in Paris. That's why most hotels provide guests with in-room safes. I also keep all of my toiletries in their bag when not in use so that my tweezers don't get accidentally swept up by the cleaning staff. Loose change on the side table may be mistaken for a tip. Expensive electronics should be locked up, or even locked in your suitcase.

Some hotels also have a safe at the front desk. But if you're super paranoid, leave valuables at home; cash, cards and passport should be carried on your body in a hidden money belt.

As for personal safety, never open the door of your hotel unless you know who it is. If you're worried it's someone posing as a hotel staff member, call the front desk to confirm "turndown service" or just tell them to leave whatever it is they're delivering at the door.

Women afraid of traveling alone may want to invest in a travel alarm that attaches to the doorknob and goes off if the door is opened (obviously only use when you're in the room).

Checking Out

Most hotels require guests to check-out at 11am or noon. Sometimes late check out is available (often for a fee) with advanced notice. Luggage rooms are usually available to store your bags for the afternoon if you have a late departure.

Look carefully at the bill when departing, as it's much easier to handle any problems/issues on the spot than once you're back home. The Tourism Tax (about €1.50 per day, depending on the star rating of the hotel) is sometimes part of the rate, and sometimes added at the end of your stay.