Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) said: It is from the Sunnah that a man (i.e. the imam) stands, with two men standing behind him and a woman standing behind the two of them.
Al-Bazzar recorded it. Its chain contains a narrator, al-Harith, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2527