Same description as for its twin photo. On this side, the striking contrast between the sunlit and the shadowed part of the building is even more evident. No post processing apart from some tone balancing. As Leora noticed, the part of the sky below the arc is flared and has a stronger yellowish tone than the rest of the sky.
Hi Alberto, this is so exciting. We get to see the other side of the rainbow. You must have had an elevated location to be able to catch both ends. And I love that you have framed the Eiffel Tower with these two photos in your portfolio - could almost be a tryptich.
It appears that the sun is hitting this building very hard - there is a shadow of another building - maybe yours? What angle do you think the sun was to cause this rainbow and circular helation? I will have to do more research on rainbows. They are always surprising.