Police in Paris have fired tear gas at protesters near the Champs-Elysées shortly after France's annual Bastille Day military parade.
Earlier, yellow-vest protesters booed President Emmanuel Macron as he was driven down the boulevard.
Police said they had detained more than 150 people, including two yellow vest leaders accused of staging an unauthorised demonstration.
The parade also saw a French inventor zoom past on a futuristic flyboard.
Franky Zapata - a former world jet ski champion - soared above the avenue and the assembled dignitaries.
More than 4,000 members of the armed forces marched down the avenue in a tradition that dates back to the years following World War One.
German Chancellor Angela Merkel was among the foreign leaders present for the event, while German, Spanish and British aircraft took part in the fly-past.
Mr Macron announced on Saturday that France would set up a new space defence command in September - following similar moves by the US, China and Russia.
He said that the command would help to "better protect our satellites, including in an active way".
There had been calls on social media for so-called yellow-vest protesters to use the national day celebrations to renew their demonstrations against President Macron.
Before the shocked gaze of tourists and other onlookers, groups of protesters - some masked - dragged metal crowd-control barriers into the centre of the Champs-Elysées to form barricades, and set fire to bins.
Riot police who had been deployed en masse were ready for trouble and dispersed the initial demonstrations with tear gas and baton charges, but pockets of trouble continued flaring up.
It's reminiscent of some of the yellow-vest disturbances from a few months ago - though it's hard to say how many of today's protesters are far-left activists or opportunist trouble-makers.