There are a number of photos of bits of Galois's notes floating around online, such as here and here. But where are the remaining originals, physically? I'm hoping what remained of them wasn't tossed out once photos were taken.
The MAA site has an Index to Mathematical Treasures, listing special collections of works by Galois.
Treatises on the Solution of Algebraic Equations. (German edition, 1889). This was a posthumously published collection of correspondence and research papers from 1828-1832 by Abel and Galois.
A site named 'Galois Group' (Link) apparently has an archive of Galois' notes and (now defunct) links to documents and school reports by Galois. The site is run by someone named Bernard Bychan (Link to his website) and it mentions that:
most of the original texts of Evariste Galois are not easily available, if you are not in working distance of Paris or at least a university with a huge library.
This suggests that Bychan knows where the notes are collected. So, you could potentially drop Bychan a message on the contact (Link) section of the site to ask.
To find works like these, it may be worth looking through the collections of university libraries and associated organisations. It may also be worth looking through biographies for references to original notes.