This is the classic loan, with fixed monthly payments, defined at contract signature. Monthly payments cover interest and principal repayment.
The in fine loan
This loan is more specifically geared to rental investors.
The borrower only reimburses interest since the principal is paid back all at once, at the end of the loan term. To pay the principal, the borrower can sell his/her property or, and this is the simplest solution, set up savings by making monthly payments to an investment product of the life insurance, Sicav, etc. type for the entire duration of the credit.
The advantages of the in fine loan are twofold :
a tax advantage since the borrower can deduct all interest paid from his/her rental income
significant cash flow, you only pay the interest (and insurance) every month