That is true. There is also pics of Leningrad with streets with signs telling not to worry about the "Finnish side" of the street as there would be no artillery fire from there, nor did we ever bomb the city. This was a decision by Mannerheim, and somehow Hitler never truly requested him to do a thing about it. So far it seems Mannerheim considered it a politically wise move with the US political pressure being one of the major reasons behind it ( FDR saying that Finland would not be treated with silk gloves after war if Finland attacked Leningrad ). Also after war it was said Mannerheim knew "the best" which was that not being too aggressive led to peace negotiations in Sept 1944 and the separate peace treaty.

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