They're getting a flat fee of $100m AUD and World Rugby are running the whole thing (tickets etc.) and making all the profits from what I understand. Not sure what costs there would be beyond the usual costs of attending a world cup but cheaper you'd assume given it's at home - all tournament costs would go into the JV. Tournament hosting fee is covered by Governments / cities who benefit from the tourists so nothing to do with Rugby Australia.
Whilst you mentioned France who made a balls of it, the RFU netted out with about $150m AUD from 2015 (about $30m of that was Twickenham profits though so not like for like so call it $120m net). My understanding is one thing the RFU did rally well which the French made a balls of was managing Tours - the independent tour operators were sending people over without the French getting much of a cut. If I had to guess further, World Rugby know they can profit from this themselves rather than Rugby Australia. World Rugby are located just up the road from there the Lions (and that's where the Lions and by extension Rugby Australia are making a packet from as well) are in Dublin & there's big cross over.
Given its 12 years on, it feels right that an overall $120m AUD would go up a fair chunk from organising the tickets / tours so probably a realistic number that Rugby Australia are taking less ($100m AUD) in order to guarantee themselves the money given the issues they've had. It's also includes the 2029 Women's World Cup.
See below with World Rugby starting the ticket thing, Rugby Australia would have done it themselves before.
World Rugby has announced the selection of Ticketmaster as the Official Ticketing Service Provider for Men's Rugby World Cup 2027 and Women's Rugby World Cup 2029, both to be hosted in Australia.
www.world.rugby