A flat tube for use with a heat exchanger. The flat tube including wide sides, narrow sides, an inner insert, a wall that at least partially forms the wide sides and the narrow sides, and the wall is configured to be produced from a punched-out blank. The flat tube further includes an introduction bevel in order to facilitate introduction of the inner insert. The introduction bevel includes at least two bent-down projections at an end of the flat tube. The at least two projections extend over portions of at least one of the wide sides and the narrow sides, and it being possible for the at least two projections to be separated off after the introduction of the inner insert.