In France, we have a type of bank loan where the borrower already has a sum of money placed as collateral and repays the loan in one go at the end.

This is called a "credit in fine" (in english bullet loan): the borrower already has the money that the bank will block in an account. The borrower will only pay the interest for the duration of the loan and repay everything at the end. This allows the bank to be certain of being repaid and the borrower to leverage with a low interest rate.