An arrangement for fluid-tight connecting of lines including a first and second connection element. The connection elements are aligned with each other and are connected by fastening means. The arrangement includes an intermediate element between the connection elements and a holding element and a second sealing element. A first sealing element is arranged in the holding element between the sealing surfaces of the connection elements. The holding element has a hollow wall with a first and second edge. The second sealing element is connected to the holding element on the second edge. The intermediate element includes an indentation extending from a first end formed on an outer side of the second sealing element to a second end formed near the first sealing element. The first end has a conical shape, wherein oppositely arranged side walls of the indentation rest on one another on the outer side of the sealing element.