Does the validation of an ICAO licence allow you to fly internationally?
When doing the validation e.g. in France you will get a validation from an EASA member which enables you to fly an EASA registered plane world-wide. 

EASA includes registered planes from 

Austria
Belgium
Bulgaria
Croatia
Cyprus
Czech Republic
Denmark
Estonia
Finland
France
Germany
Greece
Hungary
Iceland
Ireland
Italy
Latvia
Liechtenstein
Lithuania
Luxembourg
Malta
Netherlands
Norway
Poland
Portugal
Romania
Slovakia
Slovenia
Spain
Sweden
Switzerland
United Kingdom