▁soon ▁as ▁possible . ▁ ▁Comple tion ▁ ▁The ▁cost ▁of ▁completion ▁of ▁the ▁new ▁house ▁during ▁ 1 8 7 4 ▁was ▁more ▁than ▁ 7 . 5   mill ion ▁fran cs , ▁a ▁sum ▁that ▁greatly ▁exceed ed ▁the ▁amounts ▁spent ▁in ▁any ▁of ▁the ▁previous ▁th ir teen ▁years . ▁The ▁c ash - stra pped ▁government ▁of ▁the ▁Third ▁Republic ▁res orted ▁to ▁borrow ing ▁ 4 . 9   mill ion ▁gold ▁fran cs ▁at ▁an ▁interest ▁rate ▁of ▁six ▁percent ▁from ▁François ▁Bl anc , ▁the ▁wealth y ▁financi er ▁who ▁managed ▁the ▁Monte ▁Carlo ▁Cas ino . ▁Sub sequently ▁( from ▁ 1 8 7 6 ▁to ▁ 1 8 7 9 ) ▁G arn ier ▁would ▁over see ▁the ▁design ▁and ▁construction ▁of ▁the ▁Monte ▁Carlo ▁Cas ino ▁concert ▁hall , ▁the ▁S alle ▁G arn ier , ▁which ▁later ▁became ▁the ▁home ▁of ▁the ▁Op éra ▁de ▁Monte ▁Carlo . ▁ ▁During ▁ 1 8 7 4 ▁G arn ier ▁and ▁his ▁construction ▁team ▁worked ▁fe ver ish ly ▁to ▁complete ▁the ▁new ▁Paris ▁opera ▁house , ▁and ▁by ▁ 1 7 ▁October ▁the ▁or chestra ▁was ▁able ▁to ▁conduct ▁an ▁ac oust ical ▁test ▁of ▁the ▁new ▁aud itor ium , ▁followed ▁by ▁another ▁on ▁ 2 ▁December ▁which ▁was ▁attended ▁by ▁officials , ▁guests , ▁and ▁members ▁of ▁the ▁press . ▁The ▁Paris ▁Opera ▁Bal let ▁dan ced ▁on ▁the ▁stage ▁on ▁ 1 2 ▁December , ▁and ▁six ▁days ▁later