<p>This article takes a look at France’s <i>Parti animaliste</i> (<i>PA</i>) to investigate the circumstances surrounding the existence of “niche parties”. With support from field theory and the idea of boundary work, it is proposed to view niche parties as parties proposing specific goods to be acknowledged within a political field that has its own agenda and its own rules of play. An offshoot from the animal rights movement, the <i>PA</i> has found its niche by transforming the fundamentally anthropocentric “principles of vision and division” of political representation. However, this new political offer is put to the test by the boundary work of a range of actors in the political field. Two-way assimilation mechanisms are observed, enticing <i>PA</i> representatives to move out of the niche and to make their political offer consistent with the rules of political competition while bringing established parties to extend their political offer to encompass animal advocacy. The <i>PA</i>’s capacity to stay within its niche relates to a series of practical arrangements ranging from being flexible about its manifesto and identity to being understated about its alliances with other party-political forces.</p>