PARIS -- Workers have started decontaminating some Paris schools tested with unsafe levels of lead following the blaze at the Notre Dame Cathedral, as part of efforts to protect children from risks of lead poisoning.

Paris authorities ordered last month a deep clean at schools near the cathedral after the April 15 blaze. The decontamination work is expected to be completed before children go back to school in September.

At Saint Benoit nursery and primary school, a few hundred meters away from Notre Dame, workers wearing full protective gear were cleaning up the playground Thursday.

Lead removal work at the cathedral itself is set to resume next week with stricter safety procedures after authorities suspended it last month under pressure from labour inspectors concerned about health risks for workers.