Is your broker on the Euronext member brokers list? 
If so, contact them to invest in funds through Euronext Fund Services. If not, you can open an account with one of the member brokers listed below. 

Brokers list for Euronext Fund Services

MEMBER NAMECOUNTRYWEBSITE
ABN AMRO Netherlandswww.abnamro.com
BELFIUS BANKBelgiumwww.belfius.be
BINCKBANKNetherlandswww.binck.com
BNP PARIBASFrancewww.bnpparibas-am.com
BNY MELLON (EUROPE)United Kingdomwww.bnymellon.com
BOURSE DIRECTFrancewww.boursedirect.fr
CACEIS BANKFrancewww.caceis.com
CACEIS BANK NETHERLANDSNetherlandswww.caceis.com
CICFrancewww.cic-marketsolutions.com
DE GIRONetherlandswww.degiro.com
DEGROOF PETERCAMBelgiumwww.degroofpetercam.com
EXANEFrancewww.exane.com
GILBERT DUPONTBelgiumwww.gilbertdupont.fr 
ING BANKNetherlandswww.ing.com
INSINGERGILISSENNetherlandswww.insingergilissen.nl
INSTINET EUROPEUnited Kingdomwww.instinet.com
INTERACTIVE BROKERS (EUROPE)Switzerlandwww.interactivebrokers.com
JEFFERIES INTERNATIONALUnited Kingdomwww.jefferies.com
KBC SECURITIESBelgiumwww.kbcsecurities.com
KEMPENNetherlandswww.kempen.com
KEPLER CHEUVREUXFrancewww.keplercheuvreux.com
KEYTRADE BANKBelgiumwww.keytradebank.be
LELEUX ASSOCIATED BROKERSBelgiumwww.leleux.be
ODDO BHFFrancewww.oddo-bhf.com
OPTIMIX VERMOGENSBEHEERNetherlandswww.optimix.nl
PROCAPITAL SECURITIESFrancewww.procapital.fr
RABOBANK NEDERLANDNetherlandswww.rabobank.nl
SOCIETE GENERALEFrancewww.societegenerale.com
VAN LANSCHOT KEMPENNetherlandswww.vanlanschotkempen.com
WINTERFLOOD SECURITIESUnited Kingdomwww.winterflood.com