Troussier left Sfaxien by mutual consent after they failed to reach the CAF Champions League final at the weekend.
Sfaxien fell 2-1 at home to V Club, having lost the first leg of the semi-final by the same score.
Troussier, 59, joined Sfaxien in July, saying he wanted to be closer to his Rabat-based family after working in Japan and China.
Krol, part of the Netherlands teams that lost the 1974 and 1978 FIFA World Cup™ Finals, has been hired to prepare Ahly for the 2015 CAF Champions League.
The 65-year-old Dutchman coached clubs in Egypt, South Africa and Tunisia, where he was fired by Esperance three months ago after two Champions League losses.