can a candidate ask about the compensation level before the interview

Yes, that is permitted, and the employer must be able to answer that

An applicant may ask about the compensation level before the interview, and this is not something an employer can evade by saying "we'll discuss that later." The directive actually reverses the usual order: it is not the applicant who must beg for information, but the employer who must proactively provide the initial compensation or the salary range before the first interview. This can be done by including it in the job posting itself, but it may also be provided at another time before the interview — for example in an invitation or an information package. Anyone wondering whether it must be in the advertisement itself can read more about it at must there be a salary in my job posting?.

This reversed information obligation is separate from the question of whether an employer must state an exact amount or may work with a range — the latter is generally permitted, and the method is set out at may I state a salary range instead of an exact salary?. Where the discussion often does arise in practice, however, is in the question the employer asks the applicant about their current salary. This is a different matter than the topic here — the applicant who inquires about the offer — and is treated separately.

Established in Article 5 of the directive, not yet in Dutch law

This obligation follows from Article 5 of Directive (EU) 2023/970, which requires employers to share the initial compensation or salary range before the interview, in a way that ensures the applicant can actually negotiate about it. In the Netherlands, this directive still needs to be transposed into national legislation through bill 36949, which is currently under consideration; until that law is adopted and enters into force, this is not yet a directly enforceable rule under Dutch law.