A vast deployment of anti-riot police greeted protesters carrying banners saying “No to the Ouattara monarchy”, referring to President Alassane Outtara who says the amendments will help end years of instability and conflict in the world’s top cocoa producing nation.
Several opposition political leaders were also arrested including Aboudramane Sangare, a senior figure in the Ivorian Popular Front (FPI) and Mamadou Koulibaly, former president of the national assembly.
“This is Ouattara’s democracy,” said Koulibaly after being loaded into a police troop carrier.
The draft constitution, which parliament overwhelmingly approved last week, changes the rules on presidential eligibility and establishes a senate.
Critically, it would lift the current requirement that both parents of a presidential candidate must have been born in Ivory Coast.
Ouattara’s father was born in neighbouring Burkina Faso and his rival in the 2010 election Laurent Gbagbo, refused to cede power over the issue after losing his re-election bid, triggering widespread violence.
Ivory Coast’s main opposition coalition last week called on voters to boycott the referendum.
“We are on the path to boycott,” said Pascal Affi Nguessan, president of the FPI founded by Gbagbo, during the protest Thursday.
Ouattara told lawmakers earlier this month that under the proposed constitution, the election calendar “will be known in advance by everyone, with fixed dates, so that there can no delays that could disturb our country’s stability.”
Under the draft, presidential terms are set at five years, renewable only once. Ouattara was elected to a second term in October 2015.
Gbagbo is now on trial at the International Criminal Court for war crimes in connection with the deadly unrest that followed his refusal to concede his election to Ouattara in 2010.
Some 3,000 people were killed over five months following that poll.