In so far as the ECHR and, subsequently, the Charter use the term ‘religion’ in a broad sense, in that they include in it the freedom of persons to manifest their religion, the EU legislature must be considered to have intended to take the same approach when adopting Directive 2000/78, and therefore the concept of ‘religion’ in Article 1 of that directive should be interpreted as covering both the forum internum, that is the fact of having a belief, and the forum externum, that is the manifestation of religious faith in public.

In the same recital, the EU legislature also referred to the constitutional traditions common to the Member States, as general principles of EU law. Among the rights resulting from those common traditions, which have been reaffirmed in the Charter of Fundamental Rights of the European Union (‘the Charter’), is the right to freedom of conscience and religion enshrined in Article 10(1) of the Charter. In accordance with that provision, that right includes freedom to change religion or belief and freedom, either alone or in community with others and in public or in private, to manifest religion or belief, in worship, teaching, practice and observance. As is apparent from the explanations relating to the Charter of Fundamental Rights ( OJ 2007 C 303, p. 17 ), the right guaranteed in Article 10(1) of the Charter corresponds to the right guaranteed in Article 9 of the ECHR and, in accordance with Article 52(3) of the Charter, has the same meaning and scope.

Nevertheless, the EU legislature referred, in recital 1 of Directive 2000/78, to fundamental rights, as guaranteed by the European Convention for the Protection of Human Rights and Fundamental Freedoms, signed in Rome on 4 November 1950 (‘the ECHR’), which provides, in Article 9, that everyone has the right to freedom of thought, conscience and religion, a right which includes, in particular, freedom, either alone or in community with others and in public or private, to manifest his religion or belief, in worship, teaching, practice and observance.

As regards the meaning of ‘religion’ in Article 1 of Directive 2000/78, it should be noted that the directive does not include a definition of that term.

Article 2(2)(a) of Council Directive 2000/78/EC of 27 November 2000 establishing a general framework for equal treatment in employment and occupation must be interpreted as meaning that the prohibition on wearing an Islamic headscarf, which arises from an internal rule of a private undertaking prohibiting the visible wearing of any political, philosophical or religious sign in the workplace, does not constitute direct discrimination based on religion or belief within the meaning of that directive.

In the present case, the internal rule at issue in the main proceedings refers to the wearing of visible signs of political, philosophical or religious beliefs and therefore covers any manifestation of such beliefs without distinction. The rule must, therefore, be regarded as treating all workers of the undertaking in the same way by requiring them, in a general and undifferentiated way, inter alia, to dress neutrally, which precludes the wearing of such signs.

By contrast, such an internal rule of a private undertaking may constitute indirect discrimination within the meaning of Article 2(2)(b) of Directive 2000/78 if it is established that the apparently neutral obligation it imposes results, in fact, in persons adhering to a particular religion or belief being put at a particular disadvantage, unless it is objectively justified by a legitimate aim, such as the pursuit by the employer, in its relations with its customers, of a policy of political, philosophical and religious neutrality, and the means of achieving that aim are appropriate and necessary, which it is for the referring court to ascertain.

As regards, in the first place, the condition relating to the existence of a legitimate aim, it should be stated that the desire to display, in relations with both public and private sector customers, a policy of political, philosophical or religious neutrality must be considered legitimate.

An employer’s wish to project an image of neutrality towards customers relates to the freedom to conduct a business that is recognised in Article 16 of the Charter and is, in principle, legitimate, notably where the employer involves in its pursuit of that aim only those workers who are required to come into contact with the employer’s customers.

As regards, in the second place, the appropriateness of an internal rule such as that at issue in the main proceedings, it must be held that the fact that workers are prohibited from visibly wearing signs of political, philosophical or religious beliefs is appropriate for the purpose of ensuring that a policy of neutrality is properly applied, provided that that policy is genuinely pursued in a consistent and systematic manner (see, to that effect, judgments of 10 March 2009, Hartlauer, C‑169/07, EU:C:2009:141, paragraph 55, and of 12 January 2010, Petersen, C‑341/08, EU:C:2010:4, paragraph 53).

As regards, in the third place, the question whether the prohibition at issue in the main proceedings was necessary, it must be determined whether the prohibition is limited to what is strictly necessary. In the present case, what must be ascertained is whether the prohibition on the visible wearing of any sign or clothing capable of being associated with a religious faith or a political or philosophical belief covers only G4S workers who interact with customers. If that is the case, the prohibition must be considered strictly necessary for the purpose of achieving the aim pursued.

In the present case, so far as concerns the refusal of a worker such as Ms Achbita to give up wearing an Islamic headscarf when carrying out her professional duties for G4S customers, it is for the referring court to ascertain whether, taking into account the inherent constraints to which the undertaking is subject, and without G4S being required to take on an additional burden, it would have been possible for G4S, faced with such a refusal, to offer her a post not involving any visual contact with those customers, instead of dismissing her. It is for the referring court, having regard to all the material in the file, to take into account the interests involved in the case and to limit the restrictions on the freedoms concerned to what is strictly necessary.

(see paras 30, 37, 38, 40, 42-44, operative part)