I have both rented a car (in Germany) and leased a car (through Citroen). Renting a car proved to be more cost-effective, but of course this depends on the length of stay. You don’t need to collect a lease car from France – they will deliver it to you (in our case, Munich). This had an effect on our overall cost.
Depending on your travels, most rental car companies won’t allow travel to the Balkans (they say due to not having support should you break down), which resulted in us leasing the Citroen.
Excesses are usually high when renting a car (around 3,000-5,000EUR), so ensure your travel insurance covers this.
Great question. In 2014 I rented out a Peugeot 2008 from Open Europe. This is the same deal that Tristan mentioned above.
This was by far the best option we could have imagined. You get a brand new car, full insurance, unlimited km and best of all, we never got any of the speeding tickets (a handful) that came from travelling 9000km around Europe in 42 days.
I believe the minimum time is about 21 or 28 days and it’s cheapest if you pickup and drop-off in France. We did so in Paris which I would recommend against if you can (too busy).
Everything you need to know is here: http://www.peugeot-openeurope.com/en/
Note that it applies to all French cars (Peugeot, Renault, Citroen) and this package can generally be purchased through a range of different resellers but there wasn’t a significant price difference when I was checking.