Marcello Mastroianni and Anita Ekberg star in the comedy-drama, which at one point fell into the public domain.

More than 50 years after its release, Federico Fellini's La Dolce Vita remains one of cinema's most celebrated achievements. A lush, sexually charged dramedy about a journalist's (Marcello Mastroianni) search for happiness in decadent Rome, the film won the Palme d'Or at Cannes in 1960, inspired generations of directors and still makes lists of the best movies ever made.

And no one can quite figure out who owns the thing.

Thanks to the dizzying complexities of copyright law, Paramount executives, who thought they had acquired the film fair and square more than a decade ago, on Nov. 4 sued New York-based International Media Films (IMF) in federal court over dueling chain-of-title claims. The dispute, like the legal war between Warner Bros. and the heirs of Superman's creators, illustrates the dangerous uncertainty surrounding rights issues in Hollywood and the potentially dramatic impact they can have on the studios.

Since its release in 1960, La Dolce Vita has changed hands as often as Fellini's leading man switched lovers, prompting the kind of absurdly lengthy chain of title that might cause an average moviegoer's head to spin.

Paramount's theory goes like this: The original producers assigned rights to a sales agent called Cinemat, which in 1962 granted U.S. distribution rights to Astor Pictures, which helped get the film released in America. Astor transferred rights to another entity in 1966, then another, which sold rights to Los Angeles-based Republic Entertainment.

By the late '80s, the original film had fallen into the public domain, as many foreign works had, but a change in U.S. law allowed former owners to "restore" copyrights for works that still enjoyed protection overseas. Republic is said to have filed a "restoration of copyright" for the original film and a renewal of rights for the English-language dubbed and subtitled versions sometime before selling its library to Paramount in 2000.

Make sense? Paramount thought so, but when it released La Dolce Vita on Blu-ray last year in celebration of the film's 50th anniversary, the studio received nasty cease-and-desist letters from IMF, which had created its own 50th anniversary edition of La Dolce Vita and was prepping a Broadway musical version based on its claim of ownership through a separate chain of title.

Turns out IMF had been battling in court since 2007 with a company called Lucas Entertainment, which had released a pornographic knockoff of the Fellini picture titled Michael Lucas' La Dolce Vita. (That masterpiece won 14 awards at the gay porn version of the Oscars -- including best picture, best actor and best threesome). In the Lucas case, IMF raised its own chain-of-title theory: Cinemat had instead transferred rights in 1980 to a company called Hor A.G., which granted rights to another company, then another, which then in 2001 assigned them to IMF, which filed a registration with the U.S. Copyright Office on a "restored" copy of the film.

One problem: Lucas claimed some of those agreements were forged, and in 2010 a federal judge refused to allow IMF to stop the allegedly infringing porno movie.

That means Paramount owns La Dolce Vita, right? Not necessarily. In denying IMF's claim of ownership, judge John G. Koeltl suggested the film might belong to no one. "In fact, it is possible for the Fellini film to be in the public domain," Koeltl wrote. And in October, the U.S. Supreme Court heard arguments in a separate case claiming that thousands of 20th Century copyrights -- including the original La Dolce Vita -- were unconstitutionally "restored" and should be made public.

If that case, Golan v. Holder, ends with a ruling against copyright holders, the Fellini film will be merely one of thousands of major rights headaches for Hollywood studios, which could face a choice between the loss of lucrative foreign titles or -- as with La Dolce Vita -- a legal battle that is anything but sweet.