Free software advocates are criticizing the move to penalize a company in Slovakia for failing to submit official documents via a system that only works with Microsoft software.

Eura Slovakia, a textile importer, faces € 5600 (US$7,300) in fines because it filed its tax returns on paper rather than the required online method.

Since January 2010, Slovakia has required monthly tax reports on VAT (value added tax) to be filed electronically and signed by a certified electronic signature. Since many companies don't have certified electronic signatures, the authorities offer a special Web-based application called eDane.

However, the eDane application only works with Windows. According to the Free Software Foundation Europe (FSFE), it would not run on any other OS including Apple and Linux. For electronic signatures, Eura they would need software that signs the keys. The problem is that so far, only Windows applications are certified by the state, as there was no request for certification of an application for other systems. So right now, Windows is also needed for electronic signatures, the FSFE pointed out.

The director of Eura, Franti š ek Slivka, claims the authorities are effectively forcing him to buy Windows or face a fine. The FSFE, which is supporting Slivak, issued a statement calling the situation "absurd" and said that state bodies should not promote individual vendors.

"Public administrations should use a multi-platform technical solution based on open standards that is available for everybody," said Martin Husovec, of FSFE Legal.

The situation also flies in the face of the European Commission's recommendations in the European Interoperability Framework, which says that national public services "need to be more aware of the risk of creating new electronic barriers if they opt for solutions that are not interoperable."

Eura is appealing against the fines.

Follow Jennifer on Twitter at @BrusselsGeek or email tips and comments to jennifer_baker@idg.com.