As Brazilians have protested corruption scandals in their government and called for the impeachment of their president, a Dutch artist has mounted a singular protest of his own. He says the giant yellow rubber duck that protesters have hauled into the streets as a makeshift mascot in the past month is too similar to his own creation.

The duck used in the demonstrations has X’s in place of its eyes and a Portuguese slogan across its chest that says: “We won’t pay for what is not our fault anymore.” But representatives for the Dutch artist, Florentijn Hofman, who is known for his outsize creations depicting animals, say they saw too many similarities between his rubber duck and the one used in Brazil — and they are not amused.

Mr. Hofman’s six-story-tall version of the bathtub toy appeared in a harbor in Hong Kong as part of an art festival in 2013. A Brazilian industrial group, FIESP, used a similar rubber duck in the demonstrations, and Mr. Hofman’s representatives say that it featured the same design and technical patterns of the previous work and that it’s just odd that the protest duck was produced in the same factory where Mr. Hofman’s art duck was created.

A spokeswoman for Mr. Hofman, Kim Engbers, said in an email: “Of course we want to emphasize that it is a shame that this parody is used for propaganda. Our project is meant to be nonpolitical.”