Madagascans voted on Wednesday in municipal elections, the final stage in an electoral year key for President Andry Rajoelina who seeks to consolidate his power and retain control of the capital.
Tensions arose at the opening of some polling stations, with delays or irregularities such as the absence of the head of the voting booth, an AFP journalist saw.
Rajoelina was re-elected president in the Indian Ocean island nation for a third term last year in a vote boycotted by most opposition candidates.
His party already controls the National Assembly and Senate but the opposition is vying for dominance in the big cities and the capital Antananarivo in Wednesday's polls.
Opposition candidates hope to rally support among Madagascans fed up of high inflation and cuts to water and electricity supplies.
At Antananarivo's Jean-Jacques Rabearivelo high school where 12 voting booths were set up, a district official was attacked after entering the centre, which was late opening.
"People thought I was going to give instructions to commit fraud but I am neutral," Tahina Rakotoarisoa told AFP.
Overall "the opening of the poll took place calmly across the country, without any clashes", civil society and national observer organisation Safidy said.
It has deployed more than 1,700 observers.