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http://Turo.com let's you approve of the renter so you could use that.

Be aware though that there are risks to using them since they don't have the best record on privacy/security. They had a formal process where they were leaking drivers license data via email to third parties that I helped make them aware of and they fixed. Still, the fact they even put that policy into place makes me want to share it.

Viper has an inexpensive alarm with app controls but the cellular connectivity is terrible. Seems like it wouldn't be hard to improve it and make a nice UI for checking the car in and out.

In France https://www.drivy.com/ is getting pretty big but I'm not sure in which countries they operate.

It's operating in France, Spain, Germany, Belgium and Austria at the moment.