European Union Public License

The European Union Public Licence (EUPL) is a Free Software / Open Source license. Both FSF [1] and OSI [2] recognize it as FLOSS license. In particular, it is a copyleft license, as this text from the license itself asserts:

'Copyleft clause: If the Licensee distributes and/or communicates copies of the Original Works or Derivative Works based upon the Original Work, this Distribution and/or Communication will be done under the terms of this Licence or of a later version of this Licence unless the Original Work is expressly distributed only under this version of the Licence. The Licensee (becoming Licensor) cannot offer or impose any additional terms or conditions on the Work or Derivative Work that alter or restrict the terms of the Licence.'

FSF [1] also recognizes its copyleft nature.

The EUPL license contains a "Compatibility Clause", that takes into consideration other licenses and the restrictions they can contain, obviously, to adjust compatibility with strong copyleft licenses:

'Compatibility Clause:For the sake of this clause, “Compatible Licence” refers to the licences listed in the appendix attached to this Licence. Should the Licensee’s obligations under the Compatible Licence conflict with his/her obligations under this Licence, the obligations of the Compatible Licence shall prevail.'

On the appendix, the compatible license recognized are:

'Appendix:
“Compatible Licences” according to article 5 EUPL are:
- GNU General Public License (GNU GPL) v. 2
- Open Software License (OSL) v. 2.1, v. 3.0
- Common Public License v. 1.0
- Eclipse Public License v. 1.0
- Cecill v. 2.0'

Moreover this, as a curiosity, FSF justifies that, by means of relicensing to Cecill v. 2.0 some parts of code, it could be compatible with GPLv3 [1]:

'It also, indirectly, allows relicensing to GPL version 3, because there is a way to relicense to the CeCILL v2, and the CeCILL v2 gives a way to relicense to any version of the GNU GPL.
To do this two-step relicensing, you need to first write a piece of code which you can license under the CeCILL v2, or find a suitable module already available that way, and add it to the program. Adding that code to the EUPL-covered program provides grounds to relicense it to the CeCILL v2. Then you need to write a piece of code which you can license under the GPLv3+, or find a suitable module already available that way, and add it to the program. Adding that code to the CeCILL-covered program provides grounds to relicense it to GPLv3+.'

The license has changed, between version 1.0 and version 1.1 the way that it specifies how different languages available and its constraints are handled.
In version 1.1, somehow, there is a clarification of the freedoms and rights available to the licensee.In version 1.1, next sentence is added, related to the possible future version of the licenses, by adding underlined text:

'The European Commission may publish other linguistic versions and/or new versions
of this Licence, so far this is required and reasonable, without reducing the scope of
the rights granted by the Licence.'

The new version, regarding this section, clarifies that license applies for all the languages in the same manner, by clarifying this terms with next sentence:

'All linguistic versions of this Licence, approved by the European Commission, have identical value. Parties can take advantage of the linguistic version of their choice.'

The change of this clause is because of two reasons:

1 - To protect the rights of the license and future versions of the license.
2 - To grant to all european citizens with the same rights, with no considerations applying to the language used and, because of that, with no special consideration between languages [3]:

'In point 13 a new paragraph was added, according to which "All linguistic versions of this Licence, approved by the European Commission, have identical value. Parties can take advantage of the linguistic version of their choice". This new paragraph reflects the original intention of the European Commission.'

Of course, the license is applicable outside the EU (if it was not, it would not be a FLOSS license, as it would violate the freedom of use). The license clarifies world-wide use in section 2:

'The Licensor hereby grants You a world-wide, royalty-free, non-exclusive, sub-licensable licence to do the following, for the duration of copyright vested in the Original Work'

Although the license contains no explicit anti-patent clause, it contains, somehow, an anti-patent defense, in the end of Section 2:

'The Licensor grants to the Licensee royalty-free, non exclusive usage rights to any patents held by the  Licensor, to the extent necessary to make use of the rights granted on the Work under this Licence.'

Meanwhile, the licensee can not modify, among other, patent rights received :

'Attribution right: the Licensee shall keep intact all copyright, patent or trademarks
notices and all notices that refer to the Licence and to the disclaimer of warranties.'

References:
[1] http://www.gnu.org/licenses/license-list.html#EUPL
[2] http://opensource.org/licenses/EUPL-1.1
[3] http://ec.europa.eu/idabc/eupl.html
[4] http://ec.europa.eu/idabc/en/document/7330.html