This has been defined by Europe’s directive 2023/970, bullet point 33, on the 10th May 2023:
In order to disrupt the perpetuation of the gender pay gap affecting individual workers over time, employers should ensure that job vacancy notices and job titles are gender neutral and that recruitment processes are led in a non-discriminatory manner, so as not to undermine the right to equal pay. Employers should not be allowed to enquire or proactively try to obtain information about the current pay or prior pay history of an applicant for employment.
Different countries are implementing the above directive at different paces, however it will become law in all European countries relatively soon: countries that do not follow the directive will pay the respective fines.