The plaintext for this is in French (with accents ignored).
Letter frequencies are not that dissimilar to English,
though digram/trigram frequencies are somewhat different.
Same methods apply for solving this as for solving
Vigeneres with English plaintext.
Don't be put off by the text being in French.

DIVDV YMMDW LYVBS FGMOX UVMDT GYZPY SRBHJ AIZKI KMVSI JEKSM
GRADR LVMCI KTPDR GQMMI KXZDW VMNEI JIVSW UIASY FTMTY FIUNR
FEQDH WGPZR YIKNQ EYVDI FXZDP WWXGI FSUDR WWXGC KMYTI KGMRI
ULIMK WWANR LGWMX JSTDW HEZKI KPWHW WXXQM FGQOI KHMKE LLMQQ
GHGME EMYTI DYVHX WSNEM UMMKP WHMKI FIZFM WIASP WNWTP WPWQW
IYCMT ZIVNQ WRMDR LVIHR WYVZY LVMOL WRWLI FITHR LIVRM LILTW
WGWMH VIXDR VHMKM FXMMW AXMCY HVMLM WVXZV WBMLT DITDW JIIBX
ASVRG ZMUHU MIACE FWTDW EYABP WWLTR UCKKM KXMKY ATMQQ WXBDR
LHMOV GZWPY WVTDH WTTZG WQMMX VYDDP GPQMX WRAHX WHMBI VIXKE
UIUDR LGMRX SHQQI DEDHX WWADH WTMMH VITHR LIVRM LILDW JIIBX
ASVRG ZMUHU MIACI KQCRG DIACY UCKKM KXMPY ATMTZ WRBDX JIYTE
FXQEM WIAKE IYIMX AXMCI KYKQI TVCKI WTIQP SVMRT AVISM GRTDQ
WXIAS DMALI VYUTW UPMOV WRWMW MRITX JIMWI ETTDY FQWSI MVIDB
HPWRM GRNNR UXQNR FIOQG WECMI JIIBX ASVBL AQQPY WPIBS EFCRX
ASVPY AETHI METHR LIZHI MVLTR UCTHR VVMKE JIIBX ASVCY USUAY
KXQAP WPMRW WRKDE NIKKI USUAY JEVSP GBGFI FILDP SMZOV GHCHX
VYOZD SZMBI EMARM GRLDG ZETDY JIBCI DYUHI JIKDU MMADX JELTM
LTIQY FIITK EIVSE LMWMH WPISI ETMQE LYZDI LHMKE HVMRW ASVCE
FWTDG QPQMH JITZH AJNDV WRKDH WTZDW KMWMI FXZDG WKIYI LPISQ
GWXGI JILDP SYBQI USBDH MTQRX GRLDT DEKDG WHMQR AIZPY AZIZX
JEDDV KYVDX JEVRQ AWAHS FQMBE FMYTI XEQQI LSCQR WVTDW JSCDW
SMVRM IYCME DXMQR SXMTV IYQUE HVWCY AVMCI DITDG LVQBM LIITT
SWAZK WMTXE MVICI KJZNX LIUDR LWUDG SRQPY WWYTM HVWCY AVWMX
MRMBL SYNEI EIVSI LYVDY KYZD