Tensions are high all over Europe after the terrorist attacks in Paris Friday evening.
Police were called to the airport after witnesses saw a man discarding what was described as a "suspicious item," according to a police spokeswoman.
Sussex Police detained a Frenchman after what appeared to be a firearm was found at the airport.
Sussex Police said in a statement, "Personal items and what appears to be a firearm were recovered ... However, the viability of the weapon has yet to be established."