English to French Law/Patents Law: Contract(s) contrat de distribution

X is responsible for handling the orders placed by Y in the name of the Z, to keep sufficient stock in order to be able to meet the demands for Products quoted by Y or and to ensure that the Products can be made available within the time frame agreed with Y, i.e. under the present order within 15 days from the date of receipt of the call off whereby it is understood that the minimum order quantity per call off by Y directly is 500.000 products and for orders by an individual Z products.