PROXIMUS, SA DE DROIT PUBLIC Koning Albert II-laan 27, B-1030 incorporated with limited liability in Enterprise number 0202.239.951, Register of Legal Entities Brussels EUR 3,500,000,000 Euro Medium Term Note Programme This base prospectus (the Base Prospectus) relating to the EUR 3,500,000,000 Euro Medium Term Note Programme (the Programme) of , SA de droit public (the Issuer) is valid, for the purpose of the admission to trading and listing of the Notes (as defined below) on the regulated market of Brussels, for a period of twelve months from the date of approval. Any Notes issued under the Programme are issued subject to the provisions set out herein. This does not affect any Notes issued prior to the date hereof.

Under the Programme, the Issuer may from time to time issue notes (the Notes) in the Specified Denomination(s) specified in the applicable Final Terms as may be agreed between the Issuer and the relevant Dealer (as defined below). The Notes issued under the Programme may be Fixed Rate Notes, Floating Rate Notes, Zero Coupon Notes (each as defined herein) or a combination of any of the foregoing. The minimum Specified Denomination of Notes shall be EUR 100,000 (or its equivalent in other currencies). The maximum aggregate nominal amount of all Notes from time to time outstanding will not exceed EUR 3,500,000,000 (or its equivalent in other currencies) subject to increase as described herein. A description of the restrictions applicable at the date of this Base Prospectus relating to the maturity of certain Notes is set out on pages 132-134.

The Notes may be issued on a continuing basis to one or more of the Dealers specified on page 139 and any additional Dealer appointed under the Programme from time to time, which appointment may be for a specific issue or on an ongoing basis (each a Dealer and together the Dealers). References in this Base Prospectus to the relevant Dealer shall, in the case of an issue of Notes being (or intended to be) subscribed by more than one Dealer, be to all Dealers agreeing to subscribe such Notes.

An investment in Notes issued under the Programme involves certain risks. For a discussion of these risks see “Risk Factors”.

This Base Prospectus has been approved as a base prospectus on 20 March 2019 by the Belgian Financial Services and Markets Authority (the FSMA) in its capacity as competent authority under the Law of 16 June 2006 on public offerings of investment instruments and the admission of investment instruments to trading on a regulated market, as amended or superseded (the Prospectus Law), which implemented Directive 2003/71/EC, as amended or superseded (the Prospectus Directive). The approval by the FSMA does not imply any approval of the appropriateness of the merits of any issue of the Notes, nor of the situation of the Issuer. In addition application has been made to Euronext Brussels for Notes issued under the Programme to be admitted to trading and listing on the regulated market of Euronext Brussels. This Base Prospectus has been prepared on the basis of annexes IX and XIII of Commission Regulation 809/2004.

References in this Base Prospectus to Notes being listed (and all related references) shall mean that such Notes have been admitted to trading on the regulated market of Euronext Brussels. The regulated market of Euronext Brussels is a regulated market for the purposes of Directive 2014/65/EU, as amended (MiFID II).

Notice of the aggregate nominal amount of Notes, interest (if any) payable in respect of Notes, the issue price of Notes and certain other information which is applicable to each Tranche (as defined under “Terms and Conditions of the Notes”) of Notes will be set forth in a final terms document (the Final Terms) which, with respect to Notes to be listed on the regulated market of Euronext Brussels, will be fi