The agreement can be found in the ‘My Rentals’ tab of your account, once a request has been accepted by the owner and paid for by the renter (and is accessible to both).
Click on the rental in question, select the appropriate option (‘I don’t have access to my mobile phone or I want to obtain a hard copy of the agreement’) and this will give you a version you can download.
It is also possible (by selecting the first option) to avoid having to print out the agreement (the planet will thank you for it!) using the electronic version available via our Android and iOS apps! You can give these a try by searching for us (OuiCar) in the App Store or on Google Play (there is currently no Windows Phone version available).