PARIS (AP) — The talk before the opening ceremony of the Paris Games ideally should be about its grandiose backdrop: a summer sun setting on the Seine River as athletes drift by in boats and wave to cheering crowds.

But behind the romantic veneer that Paris has long curated, mounting security concerns already have had an impact on the unprecedented open-air event. In January, the number of spectators allowed to attend the ceremony was slashed from around 600,000 to around 320,000.

Tourists were told they won’t be allowed to watch it for free from riverbanks because the French government scaled back ambitions amid ongoing security threats. Then, on March 24, France raised its security readiness to the highest level after a deadly attack at a Russian concert hall and the Islamic State’s claim of responsibility.

French President Emmanuel Macron says the ceremony could be shifted instead to the national stadium at Stade de France if the security threat is deemed too high.