Japan and Ukraine both won two gold medals apiece at the International Swimming Federation's Artistic Swimming World Series leg in Paris.
Yukiko Inui clinched the solo technical title for the Japanese on day one at the Aquatic Centre Maurice Thorez.
The double Olympic bronze medallist scored 90.5294 to triumph as the season began in the 2024 Olympic host city.
It meant Spain's multiple Olympic and world medallist Ona Carbonell had to make do with silver on 90.4893 as Vasilina Khandoshka of Belarus achieved 82.5783 for bronze.
Inui would win a second medal as she teamed up with Megumu Yoshida to win technical duet silver with a mark of 90.6474.
They were pipped by Ukraine's Anastasiya Avchuk and Marta Fiedina who managed 90.7207 as France's twins Charlotte and Laura Tremble captured home bronze on 84.6237.
Last season's overall winners Ukraine won the team technical prize as they scored 90.7889 with the last routine of the night.
That stole the medals away from the hosts at the death with France having to accept silver on 84.7119 after performing to Aretha Franklin.
Israel tallied 81.2155 for bronze.
Japan's Atsushi Abe and Yumi Adachi performed a Greek mythology routine to win the technical mixed duet on 85.8529.
Spain's Pau Ribes and Berta Ferreras scored 82.4202 for silver as Brazil's Giovana Stephan and Renan Souza took bronze with 76.8835.
The solo free, duet mixed free and highlights routine finals will be held in Paris tomorrow.
The event is the first of eight legs which will be staged this season before the Super Final in Budapest.
Russia, one of the strongest artistic swimming nations, are not present in Paris.