This is perhaps too modest a street to be classified as a boulevard. It has but a single roadway, although the sidewalks are unusually wide, especially for the Netherlands.
The two rows of trees are mature and have had their lower branches trimmed, so much of the street is visible even when the trees are in leaf. The buildings are distinctly ordinary for a boulevard. They would normally be at least one story taller, and, in the French mould at least, be faced in stone.
I believe that this is an unusually early postcard, made at a time when photography was still a novelty. That is probably what accounts for the considerable number of people gathered in the foreground.
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