Author here: nope it's not possible for address search to target all countries (but there is an option to add multiple countries if necessary). It's a take on our part to provide more relevant results to the end users. By default, the end user is pre-located via IP first and can change its country if necessary, which works well in most cases. There are so many matches possible for address search that it reduces the relevance of the top 5 results. Also, there is the option of world cities available (no constraint on countries but cities only).

wow, just did this test aswell and the 5 results it showed were everything from all over the world except for the actual Paris