Where about's do you live in Australia? We live just outside Brisbane, Queensland.
We are in the same boat as you only we have already bought a house 2 years ago. Since then I have been doing a lot of research and can probably help you with some stuff.
Our house is near Belves in Dordogne region of France. We have just come back from there and the weather was beautiful. Our garden was insane and our peach tree was loaded with peaches. Nice time of year to go due to heaps of flowers being in bloom. We only had 2 half days of rain and the rest of the time it was brilliant sunshine. The top temperatures being 26 to 28 degrees while we were there but it does get hotter (and obviously colder).
Were you born in Australia? Do you have a European passport? Depending on the answers to these questions will depend on whether you will need VISAs, etc.
Assuming you were born in Australia and have not worked in France or other European country including the UK you will most likely not be eligible for health assistance as you have not paid into the Social Services. From what I have heard health insurance is mandatory in France and you will need to take out private health cover. For my husband and I without an excess we were looking at around 4,000 per year which was basic cover. If we had say a 3500 euro excess we could probably get it down to around 2,000 euro - this is based on a young fit couple with no illnesses, etc. Your amount might be half that and would be dependent on age and your current health situation.
Drivers license - once you have been in France for almost a year, you need to surrender your Australian driver's license and transfer it for French driver's license.
There are two taxes that you will need to pay on your home (excuse me if I spell them incorrectly) - they are Tax D'Habitation and Tax Fonciere - one is due in October and the other is in December. Can't remember off the top of my head but one is paid by whoever is occupying the house as of 1 January 2014. So if you bought a house and rented it out before you moved out here - the tenant would be responsible for paying that tax.
If you go for a French citizenship, you are allowed to be a dual citizen with Australia.
If you keep money in Australia ie in a interest saving account, you need to declare that interest on your French tax return (only once you are living in France). You need to let the ATO know that you are no longer an Australian Tax Resident and they will take out a flat 10% (this is for interest accounts - not sure on other sources of income like super, property income, etc). We are still trying to find a definite answer on whether the French will also take a cut of the interest earned even though you have paid tax on it - (France has a double taxation treaty with Australia) however I think France is 15% tax so they may take a further 5% - again not sure on this.
What sort of dog do you have - certain breeds are not allowed in France. They also need to get rabies shots, microchipped and a variety of other things before they can come to France. I have been recommended Jets Pets and they should be able to give you all the info on that side of thing. Even though some breeds are allowed in Australia they may not be allowed in France eg a staffordshire cross but a full staffordshire with papers is allowed.
There is a personal liability insurance that you must have in France - someone told me it was about 30 euro a year.
How is your French? Duolingo is a great free language learning website although I think it benefits to understand a bit of French to go through it.
Well that's about all I can think of just now but give me a bell if you need any further info and I'll try and help out the best I can.