I did London Paris on Eurostar, then Emirates Paris-Dubai-Adelaide; and return from MEL to Paris and then AF back to LHR just before Christmas in Business
The only issue was having to reclaim bags in CDG and walk around to the AF checkin in the next terminal - about 30 minutes all in...................... but saved well over £ 800
The Emirates bit I booked on their website in about 5 minutes................ it's very very easy
AF I booked as a single trip standalone ticket when I was in Australia