Hello giurubino!
Im sure you can allways find some module that can helps with that but i accomplished it by making a request to the prestashop Database (ps_customer), and then inserting in the wordpress using the import tool
you can use a request like this one:
select ps_customer.id_customer, ps_customer.email, ps_customer.firstname,ps_customer.lastname, ps_customer.passwd, ps_customer.company,ps_customer.birthday, ps_customer.newsletter,ps_address.id_country, ps_address.id_state, ps_address.address1, ps_address.address2,ps_address.postcode, ps_address.city, ps_address.phone, ps_address.vat_number from ps_customer
then export it to a csv file
finally, in wordpress go to tools import and export users and customers and import the file
