Once your trademark has been registered, it will be time to blow :) But be careful not to let go completely, predators are everywhere!
If you have already set up your company, you will be familiar with the never-ending stream of letters that constantly clog your mailbox from companies of all kinds wishing to sell you their services. Among them are crooks who have sniffed out the goodies of trademark applicants. The idea is simple: pretend to be an official organization (with a shiny name like "European trademark office"), and ask for the payment of a fee for the publication of the trademark on their registers. The message is subtle, so that it is difficult to know if the payment of this fee is mandatory or not. Of course, you don't have to pay anything at all, as these companies have nothing to do with the organizations with which trademarks are registered.
In the end, it is enough to remember that at the time of filing, all the fees to be paid to the INPI have been paid. There is nothing to add afterwards. In any case, always make sure that the document you receive comes from the organization with which you filed the trademark.