An opera that pokes fun at opera seria? An opera that features backstage preparations for a show, followed by an opera within an opera? Sounds familiar? No, it’s not Richard Strauss' Ariadne auf Naxos. The opera in question was composed almost 150 years before that famous work: L'Opera Seria (1769) by the Viennese court composer Florian Leopold Gassmann (1729-1774). It is a lively and amusing meta-opera with a satirical libretto by Calzabigi (who was also Gluck's collaborator in Orfeo and Alceste) which parodies Metastasian opera, and a score that manages to make fun of various conventions of the genre but without overt cynicism.

A new production of this opera has just opened in Brussels at the Cirque Royal, which is one of the venues La Monnaie is relocating to during the refurbishment of its opera house. It is conducted by the Flemish early music master René Jacobs, who originally gave the modern première of this work back in 1994 at the Schwetzingen Festival, followed by further productions in Berlin, Innsbruck and Paris. In the pit (although there’s no pit in this production) is the enterprising Ghent-based period instrument orchestra B’Rock reinforced by the musicians of the Monnaie orchestra.

Cirque Royal (built in 1878) is a large, circular auditorium with a stage at the front, and architecturally it is impressive but I imagine acoustically it could be tricky. For this production, Anglo-Irish director/designer Patrick Kinmonth removed the arena seating and placed a second stage n the round in order to visualise the two layers of the opera. The two stages were linked by a bridge, and the orchestra was placed on the arena floor in between the two stages – the strings and fortepiano on one side of the bridge and the winds and harpsichord on the other. Jacobs had to conduct facing whichever stage the singers were singing on, which meant that at times he had his back to his musicians. It couldn't have been the easiest venue to conduct, but he just about held everything together with his enthusiasm for the work.

The plot itself is not particularly complicated, but as it features a large number of characters (11 named characters) with outrageously silly names that it did take me a while to work out who is who! In three acts, it tells the story of the creation and première of a fictional opera called L’Oranzebe, and the characters include the insecure composer Sospiro, the light-headed librettist Delirio, the bankrupt impresario Fallito, the primo uomo Ritornello, and the three sopranos, Stonatrilla (Out-of-Tune), Smorfiosa (Simpering), and Porporina (Purple-faced). And there are also the three “stage mothers” of the divas – who spend most of the time sitting at the dressing tables placed around the rehearsal stage – hilariously sung in drag by two countertenors and a bass. Calzabigi and Gassmann are so skillful and spot on in the parody of these stereotypes, and interestingly, the back-stage scenes in particular doesn’t feel dated at all.

The first two acts were staged in 18th-century costume; and the opera within the opera in Act III (on the main stage) was presented in an overblown Baroque style with an oriental pavilion and stylized costumes. However, the opera is interrupted by loud booing and heckling from the disgruntled audience – played by members of the production planted all over the auditorium – and the theatre soon turned into an uproar. In the final scene, the director adds an extra layer to the meta-opera as all the singers reappears in modern dress (except for the tenor who remained in Baroque dress!), suggesting the modernity of the work.

]Musically, one sensed a great camaraderie within the cast. It must have helped that some of the singers had previously sung with Jacobs in the Champs-Elysées production, including sonorous baritone and natural comic Pietro Spagnoli (Delirio), rich-voiced and suitably diva-like soprano Alex Penda (Storitrilla) and agile high tenor Mario Zeffiri (Ritornello), who played the typically vain tenor (that couldn’t get his words right) to hilarious effect. Marcos Fink was the pompous impresario Fallito who tries to run away with the earnings at the end, and tenor Thomas Walker sung the stressed and sighing composer Sospiro (surely a precursor of the composer in Ariadne!). Lyric soprano Sunhae Im, one of Jacobs’ regular collaborators, was both crafty and charming as Porporina, playing the trouser role in the opera scene.

Because of the parodic nature of the work, it is difficult to ascertain Gassmann’s genuine compositional style, but he is certainly highly versatile in the comic idiom. His music is gently satirical but never cynical and there is a warmth that speaks to us. A contemporary of Haydn’s (three years older) and a link between Gluck and Mozart in Vienna, there were moments when I felt that Mozart’s operas such as his Magic Flute were just around the corner. Perhaps it is an one-off even within Gassmann’s oeuvre but it is an appealing opera that holds a lot of theatrical truths, and bravo to Jacobs for continuing to advocate this work.