Thousands of protesters rallied in central Vienna against Austria's new coalition government of conservatives and far right, during its swearing-in.
Among the banners were ones saying "Don't let the Nazis govern".
The Freedom Party (FPÖ) - the junior partner - is the only far-right party to get into power in the EU.
The FPÖ and People's Party (ÖVP) plan to implement stricter rules for asylum seekers, after immigration proved a major concern for Austrian voters.
The coalition says Austria will stay in the EU. The new chancellor is Sebastian Kurz, 31 - Europe's youngest leader.
There was a heavy police presence outside the Hofburg Palace during the swearing-in.
About 6000 people demonstrated against the new coalition, the BBC reported.
The FPÖ was founded by former Nazis in the 1950s, but today it denies any connection with Nazi ideology.
The FPÖ has received some key posts in the coalition, taking charge of interior and defence, and being allowed to choose the new foreign minister.
The FPÖ has a co-operation agreement with the ruling United Russia party of Russian President Vladimir Putin and the FPÖ says it wants to get the EU sanctions on Russia eased.
The new foreign minister, Karin Kneissl, is a Middle East expert who speaks Arabic and Hebrew.
She has accused German Chancellor Angela Merkel of "negligence" by allowing in record numbers of migrants.
Controversially she also said the turmoil in the Arab world was partly caused by young unemployed men "who cannot find a woman today" because of their low status.
Tough on asylum
The coalition plans to make asylum seekers hand over any cash they have when they submit an asylum claim, so that it funds their welfare.
They will also have to hand over their mobile phones so that the authorities can see from their data how they reached Austria and whom they contacted. Phones will not be confiscated but there will be systematic checks.
The FPÖ was in a coalition government before, in 2000. Back then there was a huge outcry and the government was left diplomatically isolated in the EU. But this time the reaction has been far more muted.
Migrant pressure
In 2015 Austria was at the heart of the EU's migrant crisis, when more than a million asylum seekers arrived, hoping to reach Germany. Most did move on to Germany, but Austrian resources were severely stretched and the crisis fuelled anti-immigration sentiment.
Many were refugees from the wars in Syria, Iraq and Afghanistan.
In the third quarter of this year, asylum applications in Austria were about 25% lower than in the same period of 2016, Eurostat reports. In Germany the numbers were more than 75% lower.
According to the new Austrian government's plans:
- Basic care will be provided for migrants in kind - no longer in cash benefits
- Doctors providing basic medical care for migrants may have to provide more information than in the past, as "their duty of confidentiality will be limited", the coalition programme says (in German)
- Spouses will be barred from Austria in cases of polygamy, forced marriage or child marriage
- Asylum seekers' children will have to attend special "bridging" classes in migrant hostels, separate from mainstream education. The coalition does not explain how that system will work. Many hostels are in small towns and lack resources for such classes, Austria's Der Standard newspaper reports.
In a Facebook post, FPÖ leader Heinz-Christian Strache said (in German): "No longer will it possible for migrants who haven't worked here a single day and have paid nothing into the system to get thousands of euros in social security!" He added: "On this point we in the Freedom Party have stuck to a central electoral promise!"
The Danish government was widely criticised in Europe when it introduced similar measures.
- BBC