The Shulhan Aruch (Orah Haim 453:1) writes that since they do not ferment, rice and other legumes are permissible for consumption on Pesah. The Rama (ibid.), however, notes that rice and legumes (“Kitniyot”) were forbidden in Ashkenazic lands because they often came into contact with actual Hametz and by cooking them once may accidentally consume Hametz on Pesah. Another reason is that, since bread could also be made out of rice, corn and the like, those who were unlearned might confuse that which is permitted and that which is forbidden. As such the Haye Adam mentions that Ashkenazic rabbis forbade legumes altogether, including beans. By and large the Sephardic community accepted the Shulhan Aruch’s ruling, with the exception of some communities, namely in Morocco. Rabbi Ya’akov ibn Tzur (Mishpat Utzdaka BeYa’akov vol. 1, § 9) writes that the rabbis of Morocco unanimously proscribed rice on Pesah out of concern that bran and kernels from actual Hametz grains were mixed in with them. Regarding other Kitniyot, Rabbi Yosef Benaim (Noheg BeHochma), Rabbi David Ovadia (Nahagu Ha’am) and Rabbi Haim Messas (Leket HaKemah) explain that although the rabbis did not expressly forbid them, they were of the opinion that they should be avoided on Pesah. The HIDA (Mahzik Beracha § 467), and among the Turkish community, Rabbi Haim Palagi (Lev Haim, vol. 1, § 92) discuss the restriction on Kitnityot as well.
Interestingly, besides the general Moroccan custom, there were individual families who had their own stringencies. For example, some families avoided chickpeas on Pesah since the Arabic word for them (“Hummus)” sounded similar toHametz. Other families did not use sugar since bread was sometimes dipped in it, and therefore it could have contained crumbs. One who has a known family custom should maintain it, in addition to the broader custom of not consuming rice on Pesah.
Summary: According to the Moroccan custom, rice is not permitted onPesah. Although not expressly forbidden, the custom is to avoid otherKitniyot as well.