For the Festival Printemps des Arts de Monte-Carlo's fourth and final instalment of Beethoven's String Quartet series, the baton was handed to the Quatuor Renaud Capuçon, who gave us the first and last of the five late quartets. But first, in the gloriously opulent Salle Garnier – part of the same building as the Monte Carlo Casino – something completely different...

The late German-Argentine composer, Mauricio Kagel (1931-2008), a featured composer at this year's festival, was known for introducing elements of theatrical performance into his compositions. For Kagel, the bandoneon was a bit of a find – like him, it is of German origin but was brought to Argentina. It was introduced to him by American experimental composer and pianist David Tudor, who played the instrument. Kagel wrote Pandora's Box (in 1960) for the instrument, and for Tudor. Kagel treats the bandoneon like a magic box: it hisses, whines, shakes and rattles, and in this ten-minute performance piece, the performer, here the captivating Jean-Étienne Sotty, spins on a revolving chair, laughs, hums and whistles as he plays. There were times when Sotty almost wrestled with the instrument – or was it wrestling with him? It was as if he was trying to get to something hidden deep inside the box. He flicked the buttons and keys – on of the buttons even flew off the instrument and had to be collected by Sotty during the applause – and had the bandoneon falling from his knees like a slinky toy. This was certainly out there, as an opener to an evening of Beethoven, but given that the latter, in his time, was interested in pushing the piano, for example, to the limits of its percussive abilities, perhaps he would have agreed. It was certainly an engaging performance of this intriguing piece.

Following on from the Signum Quartet's Beethoven concert in the drier acoustic of the Musée Océanographique the previous night, the sound in this concert was much fuller and warmer. This had pros and cons: Capuçon and friends certainly produced a rich, full-bodied sound, evident immediately from the opening chords of the String Quartet no. 12 in E flat major, with an equally warm yet soft-toned opening to the Adagio which followed. They brought a touch of lightness to the Andante variation and a sombre darkness to the Minore, the lyrical heart of the quartet. Yet when they added greater edge, even aggression, to their playing, the harmonic shifts became a little indistinct, particularly in the Scherzo. They negotiated the joke ending here with deadpan precision, however, and their foot-stomping energy in the finale was impressive.

Cellist Edgar Moreau handled calmly a false start to the String Quartet no. 16 in F major due to a tuning peg malfunction, the quartet retiring briefly to rectify the problem. An excess of humidity was the culprit, which may also explain Capuçon's occasional minor lapses of accuracy at the very top of the fingerboard. But these issues were more than compensated for in the controlled light and shade of the opening movement, with the contrast between its angular opening theme and the moments of pleasant serenity that follow. They took the Vivace at a rapid lick, yet held on to it with impressive precision. Once again here, in the wilfully relentless A major climax, the Capuçons' harsh attack, whilst dramatic, distorted the shocking harmonic shift. Their “Song of repose or peace”, as Beethoven described his Lento assai third movement, was exquisitely tender, with some beautifully warm and lyrical playing. Their finale – which Beethoven annotated with labels “The hard-made decision”, “Must it be?”, “It must be” – was indeed decisive and emphatic. The frequent questioning by the viola and cello was answered in perfect unity by the violins. They gave the portentous Grave questioning interruptions due weight, yet softened their tone beautifully to bring us a sense of wellbeing in the music's response, with throbbing violins over the cello's folk-like melody. The questioning swept to one side, the Quatour Renaud Capuçon left us with a feeling of resolution and acceptance.

Nick's press trip to Monte-Carlo was funded by Printemps des Arts