Free movement for persons
Originally, the free movement of workers was one of the so-called four freedoms in the EU, established by the Treaty of Rome from 1957. The other freedoms were the free movement for goods, services and capital - in addition to the right for the free establishment.
Different court cases and the Union citizenship concept in the Maastricht Treaty has given the right to move and settle in another EU country to every Union citizen, not only to workers or self employed.
All Union citizens can travel for free in the whole of the EU by having a passport or an ID Card of your own choice. You can stay in another country for 3 months. If you are applying for a job you can stay for 6 months - or even more if you have a chance to find a job.