Lemand, had responsibility for investment funds and investment management licensing, as well as being the senior economic adviser working on the impact of the financial markets performance and listed companies on the economy of the UAE.
He had been in the post since July 2008 and the sources said he resigned his position about a week ago.
Lemand, who holds a PHD in financial econometrics from the École Normale Supérieure in France, had previously worked as a senior portfolio manager at Fortis Investments in London and Paris. He is also the author of two books on financial contagion and a number of research articles on financial correlation.