5.  The applicant was born in 1971.
6.  In connection with an investigation into an international prostitution ring, measures were taken to intercept telephone conversations in accordance with Article 706-95 of the Code of Criminal Procedure, on one mobile telephone line in particular: from 5 p.m. on 6 August 2009 until 8.39 p.m. on 19 August 2009, on the basis of an order of 5 August 2009 by the Chambéry judge responsible for matters concerning civil liberties and detention (“the liberties and detention judge”), authorising interceptions for two weeks; and from 28 August 2009 until 11 September 2009, on the basis of an order of 26 August 2009 by the same judge. Two conversations with a person using a mobile phone belonging to a certain I.K., which were recorded on 4 September 2009, appeared to incriminate the applicant: one between a woman identified as R.G. and a man known as Kiril, later identified as the applicant, and the other between the same woman and another man, in which the same Kiril was referred to in terms suggesting that he was involved in the prostitution ring.
7.  A judicial investigation was opened on 2 October 2009 into alleged offences of living on the earnings of prostitution with aggravating circumstances, committed as part of an organised gang; trafficking in human beings, committed as part of an organised gang; and criminal conspiracy. A warrant for the applicant’s arrest was issued on 28 July 2010 by Judge N.C., the vice-president responsible for the investigation at the Lyons tribunal de grande instance. After being arrested in Germany pursuant to the warrant, which had in the meantime been converted into a European arrest warrant, the applicant was handed over to the French authorities at 11.45 a.m. on 16 December 2010; he was then brought before the Strasbourg public prosecutor and immediately placed in administrative detention in Strasbourg. At 10.56 a.m. on 20 December 2010 he was brought for the first time before B.G., the investigating judge dealing with the case, who placed him under formal investigation for the above-mentioned offences. At about 5 p.m. on the same day, the Lyons liberties and detention judge, to whom the matter had been referred by the investigating judge, interviewed the applicant and remanded him in custody pending trial.
8.  Although the alleged offences were classified as serious crimes, the interviews and confrontations carried out during the investigation were not recorded, by virtue of the exception provided for in the seventh paragraph of Article 116-1 of the Code of Criminal Procedure, as applicable at the material time.
... 13.  On 17 June 2011 the applicant applied to the Investigation Division of the Lyons Court of Appeal to have various procedural steps declared void, including the order for his detention, the interviews and confrontations carried out during the investigation and the interception of various telephone conversations. He submitted two requests for preliminary rulings on constitutionality, concerning respectively the seventh paragraph of Article 64-1 and the seventh paragraph of Article 116-1 of the Code of Criminal Procedure, pursuant to which no video recording had been made of the interviews and confrontations. 14.  On 6 September 2011 the Investigation Division dismissed most of the application to have the procedural steps declared void (except for one point concerning the interception of telephone conversations), in particular restating the reason given in its previous decision of 13 January 2011. In two further judgments delivered on the same day, it referred the requests for preliminary rulings on constitutionality to the Court of Cassation. 15.  On 14 September 2011 the applicant lodged an appeal on points of law, relying in particular on Article 5 § 3, Article 6 § 1 and Article 14 of the Convention and the constitutional principle of equality. 16.  On 18 January 2012 the Court of Cassation referred the requests for preliminary rulings on constitutionality to the Constitutional Council and deferred judgment pending the Council’s decision. 17.  In a decision of 6 April 2012 (no. 2012-228/229 QPC) the Constitutional Council declared the seventh paragraphs of Articles 64-1 and 116-1 of the Code of Criminal Procedure unconstitutional, holding that by providing for an exception to the rule of compulsory video recording of interviews in connection with serious offences where such interviews were carried out during preliminary or judicial investigations into serious offences relating to organised crime or undermining the fundamental interests of the nation, the impugned provisions infringed the principle of equality. It pointed out that the abrogation of those provisions would take effect from the publication of its decision and would apply in the case of persons in police custody or under formal investigation who were questioned or interviewed from that date onwards. 18.  In a judgment of 10 May 2012 the Criminal Division of the Court of Cassation dismissed the applicant’s appeal on points of law. ... It rejected his argument that there had been violations of the Convention (he had relied on Articles 6 and 14 of the Convention and, more broadly, the right to a fair trial and the prohibition of discrimination) and the Constitution as a result of the application of the seventh paragraphs of Articles 64-1 and 116-1 of the Code of Criminal Procedure in his case. Firstly, it held that the Constitutional Council had specified that the abrogation of the provisions in question would apply only in the case of persons in police custody or under formal investigation who were questioned or interviewed following the publication of its decision, so that his argument had in that respect become devoid of purpose. Secondly, it observed that the applicant had not been questioned in police custody and that, although his interviews by the investigating judge had not been recorded on video, “this did not result in any infringement of his rights under the Convention, be it his defence rights or the right to a fair trial, seeing that he was given the option of receiving legal assistance, and had the opportunity to review the manner in which the questions and answers had been transcribed in the record, which had been approved by a registrar, to ask for any corrections to be made and to challenge, at any stage of the proceedings, the meaning and scope of his statements as transcribed”. 19.  ... Lastly, it held that “it is not possible for anyone other than the party concerned to complain of a breach of the substantive requirements governing police custody, or of the lack of a video recording of police questioning or interviews by the investigating judge, in support of an application to have a procedural step or document declared void”; accordingly, the applicant was not entitled to object that the judgment appealed against had stated that there was no cause to declare void any police questioning or interviews by the investigating judge concerning individuals other than himself. 20.  In a judgment of 28 October 2011 the Lyons Criminal Court found the applicant guilty of the alleged offences, although it dismissed the charge of trafficking in human beings. It sentenced him to four years’ imprisonment and a fine of 10,000 euros (EUR). 21.  In a judgment of 20 July 2012 the Lyons Court of Appeal upheld the judgment as to the issue of guilt and sentenced the applicant to six years’ imprisonment with a minimum term of two-thirds of the sentence, as well as imposing a fine EUR 10,000 and a five-year exclusion order from the départements of Savoie and Bas-Rhin. 22.  An appeal on points of law by the applicant – whose sole argument was that French criminal law was not applicable – was rejected by the Criminal Division of the Court of Cassation in a judgment of 12 June 2013.