1. Member States may only impose administrative requirements and control measures necessary in order to ensure effective monitoring of compliance with the obligations set out in this Directive and Directive 96/71/EC, provided that these are justified and proportionate in accordance with Union law.

For these purposes Member States may in particular impose the following measures:

(a) an obligation for a service provider established in another Member State to make a simple declaration to the responsible national competent authorities at the latest at the commencement of the service provision, into (one of) the official language(s) of the host Member State, or into (an)other language(s) accepted by the host Member State, containing the relevant information necessary in order to allow factual controls at the workplace, including:

(i) the identity of the service provider;

(ii) the anticipated number of clearly identifiable posted workers;

(iii) the persons referred to under points (e) and (f);

(iv) the anticipated duration, envisaged beginning and end date of the posting;

(v) the address(es) of the workplace; and

(vi) the nature of the services justifying the posting;