Thousands of Kurds and their sympathisers arrived in the city that hosts the European parliament and the European Court of Human Rights on Saturday to be met by heavy security both from their own stewards and French police.
Lorries blocked entrances to streets near the route on boulevards outside the city centre, a method used in France since last year's Bastille Day attack in Nice, which killed 86 people.
Turkey's consul general in Strasbourg had tried unsuccessfully to have the protest banned as Ankara, the EU and the US all consider the PKK a terrorist organisation.
Peace talks broken off
President Recep Tayyip Erdogan's government broke off peace talks with Ocalan last year and stepped up military operations in the south-east, sparking a violent response from the PKK and related groups.
The PKK chief has been in a Turkish jail since 1999, when he was captured in Nairobi.
His death sentence was commuted and changed to one of life imprisonment in 2002.
His supporters have rallied in Strasbourg every year for the last 18 years, demanding his release and greater autonomy and cultural rights for Kurds.