Police have arrested three people after five coffins were found near the Eiffel Tower in Paris, draped in French flags with the inscription "French soldiers in Ukraine", sources close to the case said Sunday.

The incident is being investigated as a possible interference by a foreign power in French affairs, they told AFP.

Around 9:00 am (0700 GMT) on Saturday, three people left the five life-size coffins on the Quai Branly in Paris near the base of the Eiffel Tower, one of the world's most visited tourist attractions.

The boxes contained gypsum, a source close to the case told AFP.

The driver of a van used to transport the coffins, who was arrested nearby, told police that he had been paid 40 euros ($43) to drive the two others and their cargo, the source said.

The man was believed to have arrived from Bulgaria the evening before.

The two others were apprehended later Saturday across town at the Bercy coach terminal where they were about to board a service to Berlin, the source said.

One of the three people was Bulgarian, another Ukrainian and the third German, the source said. They were still in custody on Sunday.

President Emmanuel Macron said last month the question of sending Western troops to Ukraine would "legitimately" arise if Russia broke through Ukrainian front lines and Kyiv made such a request.

The president was doubling down on earlier comments in which he did not rule out sending troops to Ukraine, which sent shock waves through much of Europe and unsettled allies including Germany.

The Kremlin slammed the remarks, calling them "dangerous".

French authorities have suspected foreign -- notably Russian -- interference in domestic affairs in several other recent incidents, including last month when red hand graffiti was painted onto France's Holocaust Memorial.

The three suspects in that case are believed to have fled abroad.

France suspects that Russia was behind another high-profile incident, the daubing of dozens of Stars of David on buildings in Paris and its suburbs shortly after the October 7 attack by Hamas militants on Israel.

Investigators said some of the mass graffiti, widely condemned as anti-Semitic, may have been carried out at the "express demand" of an individual residing abroad, implying a possible connection to Russia.

Moscow has denied having anything to do with it.