In use since at least 2011
Blazon: Or four palets gules
These are obviously the arms of Aragon, which probably ended up associated with Pyrénées-Orientales via the county of Roussillon. Given the significant influence that Aragon had over what is now southern France, it’s not surprising that their arms kind of end up all over this region. However, these are definitely not official arms, and their connection with the department is tenuous.