It is a threat for sure, if you are recommending dome for post of fianancial controller that means you are saying he is the best. Then how will you cross question and identify his wrong doings in future as it will lead to doubting your own recommendations. 
 
Ithink self review threat is more appropriate, than self interest. Self interest threat can also be there is such controller is involved in recommending name of audit firm , deciding remuneration or giving facilities to auditor.