The champagne corks were popping at the Swiss mission to the European Union as Switzerland voted to extend a labour accord to the ten new EU members.
But the atmosphere was decidedly flat on the streets of Brussels as swissinfo gauged reaction to the vote in the heart of the EU power base.
"Switzerland has proved once again that it is a reliable partner of the EU," said Bernhard Marfurt, head of the Swiss mission in Brussels.
"Our partnership has been strengthened and we have a solid basis for future cooperation. Both sides are very happy."
The news was also being celebrated by Diana Wallis, who heads the EU parliamentary delegation responsible for relations with Switzerland.
The British Member of the European Parliament declared herself "delighted" with the resounding "yes" vote.
Nobody at home
While celebrations were underway at the Swiss mission, the rest of the city of Brussels seemed unmoved by the outcome of the vote.
The doors to the European Commission were firmly closed on Sunday and the lights were out.
News of the Swiss result also failed to excite Belgian citizen Jan Wilmots, who was enjoying an aperitif at a café next door to the Swiss mission on Place du Luxembourg.
"Of course there is a lot of EU business done in Brussels because the EU is based here," he said.
"I had heard that the Swiss were voting on something, but I am only interested in how this affects Belgium. I don't think it is a very important moment for me."
Crashing the party
A party was in full swing down the road, but the drinks were in honour of the impending nuptials of Belgian bridegroom-to-be Cédric Deflandre.
Deflandre was too busy getting to grips with his own wedding plans to consider the implications of the vote in Switzerland.
But he did hint that it might sway his choice of honeymoon venue.
"We were going to go to Fiji, but if this vote means it is easier for us to get into Switzerland then maybe we will change our tickets," he said.
Most of the local residents of Brussels canvassed by swissinfo were oblivious to the nationwide vote in Switzerland, but a few had some idea of what the ballot was all about.
The same could not be said for American holidaymaker Jim Standley, on a European tour from Boston, who appeared to be thoroughly confused about the whole affair.
"Does this mean Switzerland is in Europe or not?" he asked, more profoundly than he could ever have imagined.
swissinfo, Matthew Allen in Brussels
Switzerland and the EU have concluded 16 bilateral accords.
Sunday's vote on extending an existing free movement of people accord to the ten new EU member states was the seventh nationwide ballot on relations with Brussels in 13 years.
A request for full EU membership was frozen in the wake of Swiss voters' rejection of the European Economic Area treaty in 1992.