Implant for implanting in a body, in particular in a hollow organ or a vessel of a body, wherein the implant is constructed from a filament containing at least one polymer matrix material in which a magnetically heatable filler is arranged, wherein the filament has a cross section with a core-sheath structure, characterized in that the core comprises a first, in particular polymer, matrix material having a first melting point and in that the sheath comprises a second, polymer matrix material having a second melting point, wherein the magnetically heatable filler is present at least in the second matrix material, wherein the second melting point is lower than the first melting point, wherein the second melting point is in a range from ≥45° C. in particular to ≤100° C.