What is the ruling on calculating the zakat on money saved in the bank as 2.5% of the amount present at the completion of a full year (hawl), knowing that the money increases and decreases throughout the year but never falls below the nisab? Is it permissible to give it to a humanitarian organization in France that undertakes to spend it on the poor around the world? Is the method of compensating for delaying the payment of zakat for several years valid, and what is the ruling on delaying the payment of zakat beyond its due time?

Your method of giving out zakat is correct. It is permissible to pay zakat to organizations known for distributing it to its rightful recipients according to Sharia. Whoever paid incomplete zakat must complete the shortfall. What is required of you is repentance for the delay in zakat, as long as it was unintentional, due to the Almighty's saying: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended" and the Prophet, peace and blessings be upon him, said: "Indeed, Allah has pardoned for my Ummah their mistakes and forgetfulness."