You should be clear when making the offer about the associated costs, and who is paying them. Usually estate agent costs will be 5-8% on top of the price - these are often quoted in the asking price, however - and the notaire costs will be a similar amount but are not usually included in the quoted price. The notaire will have an up to date schedule of the fees that they will be charging.
Assuming your offer is accepted you are now ready for the next stage - finalising the purchase. Don't be concerned that a nod of the head or a handshake can bind you into a legally binding contract, it can't. The deal is not legally binding until the first legal document is signed at the notaires office a few days later.
You will usually find the actual buying process much less stressful than you expect. The estate agent and notaire will take it all out of your hands and just get on with it. We have never involved a UK solicitor in our own purchases, and I personally see little need to. The notaire is a government employee and will act equally and fairly for both parties involved.
It is also worth visiting the mairie of the area and checking the plans for building and development. You wouldn't be the first person to buy a dream house and then find an estate of new bungalows next door. This planning information is publicly available on request - ask to se the Plan d'Urbanisation.
The notaire will draw up a Compromis de Vente, containing the details of the sale, and also containing any conditions involved. Usually these are straightforward and include little more than the legal requirement that a property be checked for lead, asbestos and so on. clearly, if you do not understand the document at all, it is worth getting it translated for you, to be sure there isn't mention of a right of way through your gaden that you know nothing of.
You can ask that conditions be added. For example, if you are buying a property that you want to renovate or a barn to convert, you can specify that completion of the purchase is dependent on the necessary planning permissions being obtained. The more conditions you impose, the more chance the seller will change his mind.
All being well, and conditions being complied with, after about three months you will need to make payment (the notaire will tell you where and when and how much) and return to the notaires office for the final signing and completion of the purchase. It is a 'tradition' that the buyer drives passed the property beforehand to check all is well, that the property has not burned down etc. Hopefully this is just a formality!
You will now be the proud owner of a property in France.
Related sections: An introduction: Buy property in France
how to choose a region to move to: Which region of france to live in
How to actually Find a property
How to finance the deal: Finances of buying in France
Completing on your purchase:Close the deal