New Caledonia's UMP/Rassemblement Party says two molotov cocktails were thrown at its Noumea headquarters at the weekend.
The Party says it was an isolated attack that caused no material damage to the building in the city centre.
It says there was no threat or demand.
A complaint has been lodged an inquiry has been opened.
The party is affiliated with the French UMP whose leader, Nicolas Sarkozy, was elected French president last week.
He scored exceptionally well in New Caledonia, attaining there in the first round of voting last month his best result of all 85 electorates.