The invention relates to a closure system constituted of a closure cap, preferably produced by plastic injection molding, and a container part that is provided with a mouth, likewise preferably produced from a plastic material. The closure cap can be screwed onto the container part and the system is provided with a tamper evidence mechanism that has to be actuated twice to be overcome. The aim of the invention is to improve said tamper evidence mechanism and its handling. For this purpose, the tamper evidence mechanism comprises an actuation tab having a twist-lock feature and being freely cut on the closure cap, and a counter-projection. Said counter-projection can be overcome by acting upon the actuation tab and is molded onto the container upstream of the counter-thread configured on the container part.