Four employees of <a href="https://www.thenationalnews.com/mena/tunisia/" target="_blank">Tunisia</a>'s state-owned railway company have been detained after the Turkish flag was flown over its headquarters in the capital Tunis. An investigation has been launched but no charges have been pressed, prosecutors said. A video clip circulating on social media this week showed <a href="https://www.thenationalnews.com/tags/turkey/" target="_blank">Turkey</a>'s flag flying over the Tunisian National Railway Company (SNCFT) offices, prompting angry comments and calls for authorities to investigate the incident some described as "intolerable". SNCFT management issued an apology on its Facebook page, saying the flag was flown "by mistake” and that they “immediately intervened to replace it directly with the national flag”. The company said there was an error in a package of flags they received to replace the old ones on its buildings, which was spotted only after the wrong standard was raised. “An investigation had been launched to determine the circumstances of this incident in order to assign responsibilities and take administrative and organisational measures in this regard,” it said. “The national flag is a supreme symbol of sovereignty and national unity, and any behaviour that may affect this symbolism cannot be tolerated in any way.” The Tunisian and Turkish flags are often confused, with both being red and white, and featuring a crescent and a star. Following its independence from France and the establishment of the republic in 1957, Tunisia decided to keep the flag created when it was part of the Ottoman Empire. This is the second time this year that Tunisia's national flag has been at the centre of controversy. In May, nine people, including the heads of the Tunisian Swimming Federation and the Anti Doping Agency, were sentenced to between three months and a year in prison after covering up the national flag at a public swimming pool during a competition. At the time, the World Anti Doping Agency had said it was removing Tunisia from its list of signatories for non-compliance with international norms. This meant that Tunisian athletes could not participate under their country’s flag until the problem was resolved. The officials were put on trial after Tunisian President Kais Saied visited the swimming pool where the competition was held and, in front of media cameras, condemned what he said was an act of treason and part of a conspiracy. The Tunisian Swimming Federation was dissolved and several officials were charged with “conspiracy against state's internal security”, as well as “forming an alliance with the intent to attack properties and individuals”, and “violation of the Tunisian flag”.