Finding accommodation can be very challenging, especially for foreigners. The private real estate market is very tight in and around Paris, with landowners who tend to be very demanding. There are several possible alternatives.
A rather painless way to find accommodation is via people already at the lab. Try to send a message to your IPhT contact to check if anyone is vacating their room or apartment when you arrive.
Since demand is very high and renters are very well protected by French law, landlords and especially real estate agencies tend to ask for a ``dossier'' that indicates your financial solvency. If you have a temporary contract (CDD) you will probably also need a guarantor, i.e. someone who agrees to pay the landowner in the event where the tenant would be unable to do so.
The majority of the accommodation renting in France is done via estate agencies.
When discussing with landlords, letting agents etc. make it clear that you work for a CEA laboratory - almost everyone has heard of CEA and knows that they are reliable employers.
Ask your employer to provide you with a contract certificate (Attestation de contrat): a signed one page document that gives the dates of your employment. It can take a couple of weeks for this document to be provided by CEA from first request. Together with your actual contract, this works well to help convince potential landlords and agents that you are a reliable person.
When visiting accommodation, people bring a folder containing the documents needed for renting. Sort of thing you might want to include in a dossier d’information to show to potential landlords and agents (and naturally a photocopy for them to keep): sometimes they have a guarantor’s letter already signed, which would seem a bit forward in other countries. Other ideas for things to include are a letter (in French) explaining your hopes and dreams (for the apartment, and just generally), university certificates, bank statements or any other confidential documents in your possession. Just add it all in there - it can’t hurt (except later when you find one of the many landlords you have talked to was really an identity thief, and has cleared out your account)
French contracts for furnished accommodation can usually be cancelled at one months notice, unfurnished with three months notice. For someone arriving in France for the first time, it might be an idea to register with the accommodation services listed on this page to begin with, in order to find somewhere adequate for the first few months and then, after you have amassed a few French payslips and other official looking documents, embark on a new search if you are unhappy with your existing accommodation.
Electricity: EDF energy is the national supplier, though there are others. There is a step-by-step process to signing up for their services on their website. If you have any way of finding out the name of the previous occupant of your property, or better yet, can get a copy of the previous bill, this seems to smooth out the process of opening an account. EDF electricity has a English speaking helpline (it may take 20 minutes but don’t give up, they do usually answer in the end). http://www.edf.com/
Phone/Internet: Orange is the national supplier, though there is competition. I think that Orange is the only supplier that can reactivate a phone line that has lapsed out of service. However, any telecoms provider can open a phone account, if you have at least a dial tone from your phone. Once again, if you know the name or phone number of the previous occupant, this helps. Alternatively, if you look carefully outside your front door, there may be a little Telecom brass plaque with an ID number on it. You need a phone line to have ADSL internet, but not for fibre/cable internet. The competing telecom/internet providers include SFR, Free, Numericable and La Poste and they all have special offers from time to time. Most deals include an extra box for streaming TV shows, whether you want one or not.
Pros: dealing directly with the private landlord of an apartment saves paying the heavy fees (up to one month’s rent) that an estate/letting agency will charge. Cons: the landlord will usually insist on seeing an employment contract before agreeing to the tenancy (which is a problem if the CEA won’t confirm when this contract will be ready…). Some private landlords are a bit suspicious of foreigners; property can go fast, particularly in Paris.
Pros: can be cheaper than finding a single studio apartment Cons: appartager.com is popular but charges a subscription fee to see all listings, the competition is sometimes heavy.
Pros: not too much trouble if rooms are available; normally don’t ask for a guarantor, often possible to stay for short term or long term periods. Cons: the services may take a few weeks after registration before they let you know if a room is available or not.
Science Accueil is an organisation providing help for international researchers settling in Paris. It offers tailored suggestions of accommodation in English, as well as many other services. In particular, unlike normal renting in Paris, they do not ask for a guarantor. The majority of postdocs here use their services.
Cité Universitaire provides accommodation for researchers and students of any age in Paris: http://www.ciup.fr/en/houses/applying-for-housing/. In the case of researchers, they also provide accommodation for families. It consists of around 40 “maisons” (residencies) in a park area in the south of Paris. Many of the “maisons” are related to countries and they try to fit people in the “maison” of their country, but this is not a rule.
It is a particularly interesting option for having accommodation on arrival: one can apply online while being abroad and without any of the French documents (e.g. french paysheets) often required in the “dossiers”. Moreover, for those interested in living in Paris, Cité is located very close to a RER B station as well as relatively close to Porte d'Orleans, so there are several options to reach IPhT from there, usually taking around an hour.
Applications for accommodation must be done here: https://bienvenue.ciup.fr/questionnaire/ . It is convenient to apply as soon as possible. The application must include a CV, a certificate from your bank (not necessarily French bank) with the account details and a proof of your future job in IPhT (ask the secretaries for an “attestation”). Other documents may be required depending on the “maison”, since they are all run independently.