Before I criticize this boulevard too strenuously, I ought to note that Marselle is in the hottest region of France, and the shade of all those trees would probably be quite welcome for three or four months a year.
The trees are so densely planted and have reached such heights that the buildings have been almost entirely obscured. I do not find this a very attractive scene - it would be more appropriate to a park than to a city street.
Boulevards are planted almost universally with deciduous trees, so that for six months of the year, the buildings are visible through the bare trees, which at least affords some opportunity to see the city as it really is.
Arcades can also be used to provide shade, and have the further advantage that they also offer excellent protection from the rain, which trees, of course, do not. It is for this reason that I tend to prefer arcade Italian cities such as Bologna to French boulevards.
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