This question already has an answer here:
As @Lennart Regebro observed in an answer to another question, while the gun turret shown in the picture above is claimed to be German and from WWI, it doesn't look like German gun turrets.
Yet, @jwenting, too, agreeing with Lennart Regebro, added that the design of that turret does not conform to neither WW1 nor WW2 German capital ship turrets and pointed out that that piece did not even belong to a battleship.
So, incidentaly, it is arosed an interesting discussion that, as far as I can tell, deserves a new topic and, hence, the following question.
Can anybody show or indicate a reliable reference explaing whether that turret belonged, as it is claimed elsewhere, to a German battleship?