Still kinda weary that it might be a game in legal limbo due to the publishers involved. Can anyone site a case where either Ocean or Interplay published a game that would of been a limited publishing contract where they did not hold onto the rights afterwards? Another World is the only game that I can think of, but that was a special case due to Delphine being involved. Rage of Mages is another... Interplay published in North America and by different companies elsewhere, which is certainly in legal limbo due to licensing issues.
Other games that Ocean Software published but are now creator-owned include Worms United and World Rally Fever, so it's definitely not unprecedented.
Looking further, Mr. Geandaud now runs a consultancy firm JG Conseils: http://www.societe.com/societe/jg-conseils-510062888.html
Strangely, I'm still having a hard time finding any kind of contact information. But as ex-manager of Amazing Studio, he ought to know what happened to the rights to Heart of Darkness. Just finding some contact information will be the first step.
Edit: More info:
"Jugement prononçant la liquidation judiciaire, date de cessation des paiements le 27 janvier 2009 désignant liquidateur Selarl Mb en la personne de me Corre bernard 58 boulevard de Sebastopol 75003 Paris. Les déclarations de créances sont à déposer au liquidateur dans les deux mois de la présente publication."
Essentially, the liquidation of Amazing Studio was handled by Mr. Bernard Corre. A search for his name and company gives this email address: bcorre (at) emj-mandataires.com