French President Emmanuel Macron condemned the "cowardly" strike in the southern Beryslav town on Thursday.
"My support goes to all volunteers who engage in helping other nations," he wrote in a post on social media site X.
Ukrainian authorities said that four men and a woman were left injured following the drone strike.
A 41-year-old man from Odesa was among those left wounded, they said.
"Russian barbarity has targeted civilians in Ukraine. Two French humanitarian workers paid for their commitment to the Ukrainians with their lives," French Foreign Minister Stephane Séjourné wrote on X. "Russia will have to answer for its crimes."
Russian terror knows no boundaries or victims' nationalities. The brave French aid workers assisted people and we will always be grateful for their humanity. My condolences go out to their loved ones. I wish speedy recovery to the others who were injured in this horrific attack. https://t.co/j5LF1Jqp83
— Volodymyr Zelenskyy / Володимир Зеленський (@ZelenskyyUa) February 2, 2024
Ukrainian President Volodymyr Zelensky on Friday voiced gratitude for their work in his war-torn country.
"Russian terror knows no boundaries or victims' nationalities. The brave French aid workers assisted people and we will always be grateful for their humanity. My condolences go out to their loved ones," Mr Zelensky wrote on social media.
"Foreign volunteers were killed and injured as a result of an enemy strike on Beryslav," Kherson region governor Oleksandr Prokudin wrote on Telegram earlier on Friday.
"The Russian army killed two French citizens. Three more foreigners received minor injuries," he added, offering his "sincere condolences to the families of the dead".
Beryslav, which sits on the Dnipro River close to the front line, has regularly been targeted by Russian drones and artillery.
On January 27, one person was killed in the region by an explosive launched from a Russian drone.