The Arenc affair began on April 16, 1975 in Marseille, France, when attorney Sixte Ugolini publicly condemned the police's kidnapping of his client, Mohamed Chérif, a Moroccan citizen with legal status.

Shortly thereafter, the general public discovered a dormant warehouse located in the port of Arenc [fr] that had been covertly used by the prefecture for more than a decade to detain non-nationals (primarily Algerians) awaiting deportation, outside of any established legal framework.

By the end of 1962, the French police aimed to restrict Algerian migration to Marseille to prevent a surge of "unemployed, sick, homeless, and socially undesirable masses.

"[1] Starting April 1963, France circumvented the "free movement" arrangement under the Évian Accords[2] by introducing "health checks" (essentially fitness-for-work assessments[3]), leading to approximately 13% of Algerians being denied entry.

As the "sanitary" measures proved inadequate in sufficiently controlling immigration,[7] the government revised the principle of free movement through the Nekkache-Grandval agreements of April 1964.

The Arenc center, starting from May 1964, was placed under the direct control of the port's specialized police station, and detention, originally reserved only for "non-admitters," was expanded to include people who were being expelled by ministerial order (arrêté ministériel - A.M.).

On July 17, 1964, the Ministry of the Interior notified the Bouches-du-Rhône Prefect regarding the same matterː[12]"As the Algerian nationals in question are not subject to a custodial sentence, it is important that during their stay at the center, surveillance measures are strictly limited to those necessary to prevent their escape [sic].

"[1] The premises consisted of three main dormitories: one for "AM/DP" (nationals subject to a ministerial order or prefectoral decision), one for women and children, and another for "non-admis" (rejected upon entry).

[17] The association Aide aux travailleurs d'outre-mer (ATOM), which has been appointed by the prefecture to manage several social reception centers in Marseille,[21][22][23] was responsible for cleaning and laundering the dormitories.

[27][29][30] His friends informed Sixte Ugolini, who was in charge of the local syndicat des avocats de France (SAF), about the existence of a clandestine detention center near the Arenc ferry terminal.

[27] On April 15, 1975, Saïd Bennia, an Algerian national born in 1956 in Marseille and a client of Sixte Ugolini, was arrested by the police immediately after he was judged free by the court.

[29][30][31] On April 16, 1975, Sixte Ugolini called a press conference to denounce what he deemed a kidnapping due to the lack of news regarding Mohamed Chérif's appearance before the public prosecutor's office within the legal period of police garde à vue.

[19][27][32] Journalist Alex Panzani reported that "immigrant circles" were aware of the center's existence[19] while historian Ed Naylor hypothesized that Sixte Ugolini's surprise during the press conference may have been staged as part of a media move.

Upon his return to Marseille, he informed his lawyer through an interpreter that he had been coerced into signing incomprehensible documents before being confined in a warehouseː[34][35]"On April 11, I went to the police summons, in an office on the second floor.

It stated that Arenc was actually a "transit center" that had been legally established in 1964 and housed individuals who were denied entry into France, foreign nationals who had received an administrative expulsion order, and illegal immigrants.

[39] A Marseilles resident, Salah Berrebouh, was sent to Algeria and barred from attending court proceedings; however, he later clarified the details of his deportation to the judge once he returned to France.

However, he avoided answering a question from Paul Cermolacce, a Communist deputy from Bouches-du-Rhône, who inquired about why the public prosecutor's office had opened an investigation.

[47][48] Gustave Essaka, a Cameroonian national who had been detained in the center for almost a month without an arrest warrant or conviction, was eventually deported and returned to Marseille before filing a complaint.

[59][60] On June 14, 1975, approximately one thousand people gathered in Marseille for a demonstration demanding the immediate closure of Arenc prison and the indictment of those responsible.

The event was organized by the Committee for the closure of Arenc prison, according to which around one thousand people attended, while the police estimated the number to be 550.

[61] Protest declined during the 1975 summer months, but in September, it was reignited by the release of the book Une prison clandestine de la police française, Arenc by Alex Panzani.

[62] At a National Assembly session on November 24, 1976, Interior Minister Michel Poniatowski addressed Communist deputy Paul Cermolacce's concerns about the Arenc center, citing it as a more humane alternative to prison.

In 1999, Sixte Ugolini commented on the ongoing tightening of detention laws since Arenc was exposed to the publicː[72]"France has simply legalized this lawless situation, and for foreigners, nothing has changed.

"The European Committee for the Prevention of Torture published a report in 1996 exposing the dire living conditions caused by the deteriorating state of the Arenc warehouse.