Is it permissible to deal with a usurious bank in France due to the unavailability of Islamic banks, and would I be sinful if I could not determine the amount of interest to dispose of it?

It is not permissible to deposit money in interest-based banks except under certain conditions: that no Islamic bank is available, that there is an urgent necessity for it (such as fear for the money from theft), and that the deposit is in a current account, not a savings account. If interest-based profits were accrued in the past, they must be disposed of by spending them on charitable causes and for the benefit of Muslims. It is permissible to estimate their value based on غالبة الظن (preponderant conjecture).