Where does the boundary between opera and real life lie? This seems to be the question that David Marton poses in his production of Richard Strauss’ Capriccio, first seen in Lyon in 2013 and now restaged by La Monnaie in Brussels. The question that the libretto asks – first the music, then the words, or vice versa? – turns out to be much the same, as Strauss’ delightful conceit of having a countess choose between two love rivals in the guise of operatic primacy emphasises. The plot’s struggle to put together an opera that just happens to be the one we’ve spent the evening watching is a masterstroke, and Marton and his designer Christian Friedländer play on this concept by setting Capriccio in a theatre – we view it side-on in cross-section, from stage to pit to auditorium. It’s an irony, in Brussels’s case, in that the company has been forced to stage it in a glorified tent on former industrial wasteland while the refurbishment of its proper opera house overruns (that old sore). Hence some competition from low-flying planes and a tumultuous rain-storm battering the thin roof threatening to drown out the opera’s final scene.

Strauss designed Capriccio to run for some 135 minutes without a break – still shorter than The Flying Dutchman or Das Rheingold – but here an interval is interposed at the point (also taken by Glyndebourne, if memory serves) where the Countess asks for chocolate to be brought in, but here replaced with a surtitled message that hot chocolate is now available in the foyer. There are other changes to the printed score, too, with a handful of ‘break-outs’, such as extra dialogue added during the first reading of the sonnet and some at first inexplicable and intrusive business with a trio of dancers both during the fugue scene and the theatre director La Roche’s big monologue. And while on the subject of the confusing, it isn’t clear why the stage is gradually filled with a forest of pot plants, unless to provide a setting for the moonlit final scene, and also what the incongruous curtains of tinsel indicate.

A lot, though, is fascinating and perceptive: the teasing idea that at any point the Countess might abandon her rival poet and composer lovers and run off with her butler – he certainly has the hots for her; and especially the ending, made even more poignant than usual by having the Countess meet images of her former and future selves in the form of the child and elderly dancers, as an alternative to her usual conversation with her reflection in a mirror – a nod, perhaps, in this Straussian retrospective of a work, to the Marschellin’s recognition of passing time in Der Rosenkavalier. If the middle dancer, seen consorting with the butler in a theatre box, is meant to be her too, then she does indeed choose the third way… (This business with the Haushofmeister, incidentally, is intriguing – he seems to have issues of insecurity, packing off all the Italian singers and dancers at the first opportunity, and was that the rest of the staff despatched in the same fashion in the closing bars, to get them out the way?)

As a self-styled ‘conversation piece’, Capriccio has always been demanding of its singer-actors, and the cast here coped with the Straussian repartee like a true ensemble. That said, Sally Matthews’ Countess struggled to project her German, and the French/Dutch surtitles had to come to the rescue more than once – this despite the occasionally intrusive microphone assistance being used to help the singers in this unforgiving venue. But her tonal richness and commanding presence were recompense aplenty. No such issues with either Kristinn Sigmundsson’s convincing La Roche or Dietrich Henschel’s eloquent Count. The rival lovers, composer Flamand and poet Olivier were less satisfactory: Edgaras Montvidas caught the character well, but his tenor sound had a swallowed sense to it, and Lauri Vasar’s Olivier was more tonally secure but was lacking in stage charisma. Charlotte Hellekant was in fine voice as the actor Clairon, and there were convincing cameos from François Piolino’s Monsier Taupe (the prompter), Elena Galitskaya and Dmitry Ivanchey as the Italian Singers and Christian Oldenburg’s lascivious Haushofmeister.

But this was really conductor Lothar Koenigs’s evening: Strauss’ score was played by the excellent Monnaie orchestra with ear-tingling attention to detail. From the phrasing of the opening string sextet prelude to the opulent heights of the moonlight interlude and final scene, Koenigs’ exquisite shaping of line and balancing of harmony were an absolute joy to hear, and he proved unfazed by both directorial breaks in the music or competition from the heavens above.