Buying to rent in france or investing capital in a bank account - which is best?

My friend has enough capital to buy an appartment or gain a small income from investing with a bank. Is buying to rent, in France a good way for them of investing their money? Is it better to rent in a large town which has many properties on the market already for renting, or a small town which is very close by. My friend will be doing all the maintenance. Is there an insurance Policy to protect landlords from non rent paying tenants. What are other peoples expériences?

Thanks Fiona