VIENNA (Reuters) - Hundreds of chanting and partying Spanish and German supporters gathered in Vienna on Sunday, transforming the historic city centre in to a big party zone ahead of the European Championship final.

Police expect around 40,000 German fans and 15,000 Spanish supporters to descend on the Austrian capital's centre as Germany take on Spain in the city's stadium only a few kilometres away.

"It's one big street party right now -- happy and loud but very peaceful," said Christian Stella from Vienna police.

Transforming the city's main square around St Stephen's cathedral in to a sea of red and yellow, Spanish fans had kicked off their party since the early morning hours, accompanied by their own marching band.

"The Spanish people are simply more fun, they know much better than the Germans how to party," said Maria de la Cruz Aparicio from Ciudad Real, who had no ticket for the match in the Austrian capital, but had flown with her family to Vienna to watch the match on one of the big screens in the fanzone.

"Spain is the winner, of course, tonight and it will be absolutely fantastic," she said standing beside a group of male Spanish fans clad in flamenco dresses and jumping up and down.

GREAT DAY

German supporters, mingling with their Spanish counterparts between dozens of street vendors flogging tops and scarves, begged to differ.

"We might need a little longer to get started but you will see soon enough that this will be a great day for the Germans and a sad one for the Spanish," said Roland Braeuer from southern Germany, dressed in lederhosen and a Germany top.

Though Vienna has the tournament's biggest fan zone stretching along a tree-lined grand boulevard curving around its city centre, the square around St Stephen's cathedral emerged as a main gathering point for fans in the run up to the matches.

"We actually wanted to do a bit of sightseeing and go down to the Danube before watching the match in the fanzone tonight," said Sylvia who had flown in from Berlin.

"But the atmosphere is so fantastic, I can't tear myself away from it -- I have to stay here," said the 56-year-old, proudly displaying a Lukas Podolski top.