Question

Why does Hugo refer to Paris as the "central shaft of the mine"?

Answer 1

It’s a very rich place a very luxurious place because usually that’s where you find the good stuff is in the center so that’s where some of the finer things are

Answer 2

Victor Hugo refers to Paris as the central shaft of the mine because soon after the word of the July Revolution (1830) in France that put an end to the Bourbon monarchy spread throughout Europe similar uprisings followed in Italy, Germany, Switzerland, Spain, Portugal, Belgium, and Poland.