Page 24 Member States shall not apply directly or indirectly to imported goods from any Member State fiscal charges in excess of those applied to like domestic goods or otherwise impose such charges for the effective protection of domestic goods. Member States shall eliminate all effective internal taxes or other internal charges that are made for the protection of domestic goods not later than four (4) years after the commencement of the trade liberalization scheme referred to in Article 54 of this Treaty. Where by virtue of obligations under an existing contract entered into by a Member State such a Member State is unable to comply with the provisions of this Article, the Member State shall duly notify the Council of this fact and shall not extend or renew such contract at its expiry. Member States shall eliminate progressively all revenue duties designed to protect domestic goods not later than the end of the period for the application bf the trade liberalization scheme referred to in Article 54 of this Treaty. Member States undertake to be bound by the consolidated import duties contained in the ECOWAS Customs Tariff for the purposes of trade liberalization within the Community. Member States undertake to avoid double taxation of Community citizens and grant assistance to one another in combating international tax evasion. 17. The conditions and modalities for granting such assistance shall be as contained in a Double Taxation and Assistance Convention. Article 41 Quantitative Restrictions on Community Goods Except as may be provided for or permitted by this Treaty, Member States undertake to relax gradually and to remove over a maximum period of four (4) years after the launching of the trade liberalization scheme referred to in Article 54, all the then existing quota, quantitative or like restrictions or prohibitions which apply to the import into that State of goods originating in the other Member States and thereafter refrain from imposing any further restrictions or prohibitions. Whereby virtue of obligations under an existing contract entered into by a Member State such a Member State is unable to comply with the provisions of this Article, the member State shall duly notify Council of this fact and shall not extend or renew such contract at its expiry. 18. The Authority may at any time, on the recommendation of the Council decide that any quota, quantitative or like restrictions or prohibitions shall be relaxed more rapidly or removed earlier than agreed upon under paragraph 1 of this Article. 19. A Member State may, after having given notice to the Executive Secretary and the other Member States of its intention to do so, introduce or continue to execute restrictions or prohibitions affecting: (a) the application of security laws and regulations; (b) the control of arms, ammunition and other war equipment and military items; (c) the protection of human, animal or plant health or life, or the protection of public morality; (d) the transfer of gold, silver and precious and semi-precious stones; (e) the protection of national artistic and cultural property;