For daytime babysitting you will often find a specialised agency such as:

They will introduce you to nannies until you find your choice.

Usually you will share the child carer with another family (that you can find through the agency, or by adverts in shops). One week you will bring your child to the other family where the babysitter will take care of them, the other week it will by at your place.

In order to register the child carer, you must contact URSSAF, which will provide you all details, such as insurance number, social security charges ...etc.

In that case the indicative price is:
3400 F/month (i.e. 39.4F/h) or 520 €/month + social security charges that you will pay to URSSAF at the end of each quarter (2300F/month or 350€). The salary is given by cheque to the nanny, with a payslip. You can claim a few allowances: AGED (Aide pour la Garde d’Enfants à Domicile) pay a part of the social charges + tax reduce (for the next year, with a maximum of 22 500F) + Paris Town Hall allowance (850F/ month or 130€). Basic working day is 10h/day.

If you are also looking for some domestic help, you will find a lot of adverts in local papers or shops. You can also pass through associations, for example:
Aida Fosad-Apsara Paris

Aide à domicile
92 bis bd Montparnasse
75014 ParisTel : 01 42 18 16 40

The price is about 85 F/hour (13 €).

You can also pay using a “chèque emploi-service” (available in post-offices) which give you the guarantee of an official state payement and a part is deductible from income tax.