A propeller for an aircraft engine for being rotated about a propeller axis of rotation, the propeller comprising a hub as well as a plurality of blades circumferentially distributed about the hub, the propeller further comprises: - a blade support associated with each blade, said blade support being pivotably mounted on said hub about an incidence pitch axis; - incidence control means for the blades configured to pivot said blade support relative to the hub, about said incidence pitch axis; - a pivoting connection between each blade support and the root of its associated blade, the pivot connection enabling the blade to be pivoted relative to its blade support about a blade folding axis; - associated with at least one of the blades, a blade folding/unfolding control member configured to pivot said blade root relative to the blade support about said folding axis, said folding/unfolding control member comprising a first element and a second element translationally movable with respect to each other, the first element being mounted on said hub using a first pin joint and the second element being mounted on a transmission device using a second pin joint, the transmission device being connected to said blade root; characterized in that the propeller comprises: - a blade folding/unfolding synchronization passive device, including a central synchronization element rotatably mounted relative to the hub about said propeller axis of rotation, as well as a connector element associated with each blade, said connector element including a first end mounted on said blade root about a first ball joint, as well as a second end mounted on said central synchronization element using a second ball joint. - a blade support associated with each blade, said blade support being pivotably mounted on said hub about an incidence pitch axis; - incidence control means for the blades configured to pivot said blade support relative to the hub, about said incidence pitch axis; - a pivoting connection between each blade support and the root of its associated blade, the pivot connection enabling the blade to be pivoted relative to its blade support about a blade folding axis; - associated with at least one of the blades, a blade folding/unfolding control member configured to pivot said blade root relative to the blade support about said folding axis, said folding/unfolding control member comprising a first element and a second element translationally movable with respect to each other, the first element being mounted on said hub using a first pin joint and the second element being mounted on a transmission device using a second pin joint, the transmission device being connected to said blade root; characterized in that the propeller comprises: - a blade folding/unfolding synchronization passive device, including a central synchronization element rotatably mounted relative to the hub about said propeller axis of rotation, as well as a connector element associated with each blade, said connector element including a first end mounted on said blade root about a first ball joint, as well as a second end mounted on said central synchronization element using a second ball joint. - a blade folding/unfolding synchronization passive device, including a central synchronization element rotatably mounted relative to the hub about said propeller axis of rotation, as well as a connector element associated with each blade, said connector element including a first end mounted on said blade root about a first ball joint, as well as a second end mounted on said central synchronization element using a second ball joint.