Aesthetics, Art and Architecture

I spent the last weekend in Paris, mostly wondering aimlessly (though once following a map-it still seemed my aim was absent) and enjoying the architecture and art works, and the way that people were living with and around it all.
The scale of the buildings and monuments is the most striking element for me. Such architectural and artistic feats would have required immense resources and a vast (skilled)
The line between art and architecture seems undefined in old Paris and old London architecture and monuments. There is consideration of statement (authority, status etc) but also of aesthetics which must surely play a part in why they have stood the test of time.
I am not sure where I am going with this (still wandering aimlessly), only that I am thinking the way we work to integrate art and architecture or capital works, can be improved, and that an appreciation of aesthetics may be a part of that improvement.