Hey Orlando,
Most long term lets in France are for a minimum of a year and are unfurnished - you also get into 2 form of Council tax, gas/electricity/TV license etc

We did what you are intending to do just over 3 years ago - Sold up in UK and rented a furnished holiday flat (out of season) by the month to get a better rate and looked round for a property - the town advice centers all have lists of rental property available and it is a deal that is easy to get out of quickly when you find the perfect place to buy...
Keep in touch