The Place de la Bastille in Paris was packed on Sunday night in celebration of Francois Hollande's narrow win in the presidential elections.
The cheers were echoed across the continent because his anti-austerity programme offers hope to the vast numbers of unemployed people across Europe.
In Spain, for example, unemployment among adults stands at one in four and among young people the figure is 50 per cent.
Hollande has pledged to cut presidential and ministers' salaries, reverse Nicolas Sarkozy's increase in the retirement age for those who have paid full insurance, freeze fuel prices and raise parental allowances for school-age children.
Assuming he wins the parliamentary elections next month, he will then attempt to push through the parliament's tax reforms which will end tax breaks for the wealthy and introduce 75 per cent tax on earnings above €1 million per year.
It is a radical programme which, linked to the introduction of a financial transaction tax, will demonstrate that there is an alternative to the austerity that has been imposed on Greece, Italy, Spain, Portugal and Ireland, all of which have resulted in rising unemployment, decreased spending power and worsening social conditions for the most vulnerable.
The response of the European right, whose two most prominent politicians Angela Merkel and David Cameron have never even met Hollande, has been predictable - ie stating that the European stability pact is not up for renegotiation and that austerity is the only way forward.
It seems that they never learn. The Tories in Britain did spectacularly badly in last week's election in Britain, and in regional elections in Schleswig-Holstein Merkel's Christian Democrats suffered big losses. They are likely to suffer even bigger losses in next week's elections in North Rhine Westphalia.
The right-wing narrative of allowing the wealthy to continue increasing their wealth at the expense of the poor is hugely unpopular across Europe.
The Greek election results ought to be a deep warning to all centre and social democratic parties of the consequences of severe austerity measures.
The once all-powerful centrist Pasok party had its share of the vote reduced to 13 per cent and the conservative New Democracy party only won about 19 per cent support.
The combined votes of the two left parties in Greece show a heightened degree of politicisation, particularly among young people who face years of unemployment as they watch industry, services and businesses close.
However, we should not get too carried away. The economic crisis has also led to the growth of racist, far-right parties such as New Dawn in Greece and the National Front in France.
Both saw increases in their support through their simple expedient of blaming all economic problems on immigration and minorities. The nazis in Germany employed exactly the same tactic during the 1920s recession.
There is now a huge opportunity for the left across Europe to embrace a strategy of investment in infrastructure and public services, and to promote higher employment.
And Europe's banking system, which is out of the control of any democratic forces, urgently needs reining in.
The 2008 financial crisis led to the partial public ownership of most nationally identified banks, but the transnational banks escaped this.
They have, however, all benefited from huge public bailouts and are being allowed to carry on in exactly the same way as they did during the credit boom of the 1990s.
Indeed, the very same banks are also making a great deal of money out of very high interest short-rate bonds loaned to the very governments that they are condemning for their alleged economic ineptitude.
The European Central Bank was deliberately created to be independent of democratic control and its function is to maintain price stability across Europe. It never had a requirement for either social or environmental sustainability.
As the ordinary people all over Europe face the problems of unemployment and insecurity, it is surely time to tame the banking system and focus on decent public services, rather than eternally mortgaging ourselves to something that we cannot control.
The European Central Bank does not have the answers to this crisis any more than the International Monetary Fund has had answers for the world's poorest people with its structural adjustment programmes.
France and Greece's election results are heartening but they have to be built on in order to see the end of this gloomy period in our history.
Like thousands of others in London last week I worked flat out to win support for Labour candidates in the London Assembly elections and the return of Ken Livingstone as mayor. While Labour did spectacularly well in the assembly elections, Livingstone narrowly lost to the incumbent Boris Johnson.
Livingstone has suffered more media attacks and abuse than almost any other Labour politician I can think of, with the Evening Standard leading the way with pages and pages of negative stories about him over the past four years.
However, he should not be downcast, and should be thanked for his incredible contribution to radical politics in London ever since he was first elected as a borough councillor in 1971.
His work on the Greater London Council (GLC) from 1973 onwards, brought about some ground-breaking policies - free bus passes for the elderly, a London-wide housing programme and, crucially, a transport policy based on buses and trains rather than private cars.
I stood and marched with Livingstone against the Tories' planned motorway for London in the '70s and against the later East London Assessment Study under which the Tory government tried to build a motorway across north and east London.
Livingstone should also be recognised for the way in which, well head of his time, he stood up for equal rights, for women and gay and lesbian communities in London.
Under his leadership from 1981 to 1986, the GLC became a powerhouse for progressive policies on individual rights and community development, helping to boost local government's role economic development.
That administration is well remembered for its popular appeal - his billboard of London's rising unemployment figures on the side of County Hall, directly opposite Parliament, was especially memorable, not least for the Tory MPs in the House.
As the first elected mayor of London, in a system that he never really wanted, Livingstone was denied the Labour nomination for mayor and stood as an independent and triumphed.
His first term saw the introduction of the congestion charge and the development of a planning policy which improved public transport and ensured that there was some social housing in all new developments.
Livingstone showed great moral principle in his determination to give a voice to all communities in London.
His promotion of the celebration of national days for Muslim, Jewish and Christian communities, as well as big events like St Patrick's Day and his support for anti-racism festivals, showed just what a progressive mayor in London could achieve.
The richest 10 per cent of Londoners are 273 times as wealthy as the poorest 10 per cent. This is the widest gap of any city in the developed world - and that is the real issue facing the London Assembly, which Johnson doesn't begin to understand.
Sadly Livingstone will not be mayor, but hopefully the substantial Labour group in coalition with the Greens on the assembly will manage to push for fare reductions, education maintenance grants for hard-up youngsters, vital council housing and control of the private rented sector in London.
We should all thank Livingstone for the huge contribution he's made to radical debate, not just in London but in the Labour Party and in a much wider community of people who want to see social justice and a fairer society.
Johnson's poverty of ambition meant that all he could do was follow through on Livingstone's programmes, including the bicycle hire scheme absurdly dubbed "Boris bikes" by the Evening Standard. How about renaming them "Kenny farthings"?
Thanks Ken, I know you won't give up the fight.
Jeremy Corbyn is Labour MP for Islington North.