The monocle-wearing Sponsz is a native of the nation of Borduria, where he became the Chief of Police of the capital Szohôd, and the head of the Secret Police or ZEP, which operates on behalf of the country's dictator Marshal Kurvi-Tasch. He is a calculating and ruthless figure, and bears strong grudges against those who upset his political machinations (such as Tintin).
Although married, Sponsz is a womanizer, flirting with other women including Bianca Castafiore to the point where rumours of engagement are cultivated by the press.
(Paul appears among the audience at Tintin's knighthood investiture ceremony at the end of King Ottokar's Sceptre. Hergé also includes caricatures of himself, his first wife and other artists.)
He even had the contents of Calculus's laboratory stolen and smuggled into Borduria where it was used in a demonstration for some leading officials. At the time the device could only break glass, but Calculus did have, on microfilm, the plans for the next stage which would include the destruction of bricks and metal. Sponsz was determined to get those plans.
Things were made complicated by the attempts of agents from Syldavia, Borduria's enemy, to kidnap Calculus for themselves, and the interference of Tintin and Captain Haddock who wanted to rescue their friend.
Tintin and Haddock eventually reached Szohôd where Calculus was being held. Sponsz arranged for them to be picked up by his agents and escorted to a luxury hotel. The two friends were put into separate non-adjoining rooms and their telephones tapped. One of the agents drunkenly revealed to Tintin that only Sponsz knew of Calculus's present whereabouts. Tintin and Haddock managed to escape the hotel to a local opera house where an acquaintance, Bianca Castafiore, was performing.
Sponsz had the opera house surrounded by police officers and attended the evening performance himself. After the show he went to visit Castafiore in her dressing-room, unaware that Tintin and Haddock, in their bid to escape, were hiding behind a clothes rack. Sponsz himself ordered some officers who were searching the building to leave the room.
Sponsz had originally kept Tintin and Haddock under surveillance for information (probably as a way of breaking Calculus). Now it was they who were discreetly overhearing his own revealing conversation with Castafiore.
Sponsz told Bianca that Calculus was being held in the fortress of Bakhine. He was being given just one more day to give up the plans for his weapon of mass destruction or else... If he did give up the plans, Calculus would then be handed over to two members of the International Red Cross to whom he would certify that he was a guest of the Bordurians and that he had given up the plans of his own free will. Their papers and his release documents were in Sponsz's overcoat, which was hanging in the clothes rake next to Tintin and Haddock.
Tintin and Haddock stole the documents and, in disguise, went to Bakhine to get Calculus out. Although the papers were in order, the prison warden insisted in double-checking with Sponsz who was not yet in his office (much to Tintin and Haddock's relief). Sponsz's secretary did give the all-clear since a document signed by Sponsz was always assumed to be in order; and he does not appear to have told them how important the prisoner was.
When Sponsz heard about this he immediately raised the alarm since he knew that he had not given the documents to the Red Cross delegates and that they were supposed to be in his overcoat. Nevertheless Tintin, Haddock and Calculus managed to cross the border out of Borduria and get away.
Calculus later found the plans for his invention and destroyed them.
Her presence at Marlinspike Hall with Tintin, Haddock and Calculus was widely reported. It may have confirmed Sponsz's suspicion that she was complicit in their escape from Borduria and he planned his revenge accordingly.
In Tintin and the Picaros, General Tapioca had become the leader of the South American republic of San Theodoros. He had the support of Borduria and his officials would wear moustaches similar to that of Kurvi-Tasch, the Bordurian dictator. Sponsz was sent to San Theodoros as an "adviser" to the regime, but pretty much controlled the Interior Ministry under the pseudonym of Colonel Esponja.
When Bianca Castafiore arrived in San Theodoros as part of a tour of South America, Sponsz took advantage of her presence to falsify documents which outlined a plan to assassinate Tapioca and planted them in her luggage. Castafiore was arrested and jailed along with her pianist Igor Wagner, her maid Irma and Tintin's friends Thompson and Thomson who were accompanying her in order to watch over her valuable jewellery. When at their trial, Bianca was sentenced to life in prison, Sponsz smugly remarked that "Revenge is sweet".
The forged documents also implicated Tintin, Haddock and Calculus. The press raised the fact that Bianca had been their "guest" for a while at Marlinspike and that they were also acquainted with Tapioca's rival General Alcazar. As Sponsz had planned, Tintin, Haddock and Calculus travelled to San Theodoros to clear their names and free their friends.
Like in Borduria, Sponsz had Tintin and his friends placed in luxurious accommodation which was filled with bugs and hidden cameras. He even sent them a manservant, a man called Pablo whom Tintin knew from The Broken Ear. Pablo told Tintin and his friends the truth about Esponja/Sponsz and helped them to escape while visiting a pyramid. From there they joined General Alcazar who also thought that Pablo was acting on his behalf. The whole thing however was a trap laid out by Sponsz and Pablo to kill Tintin, Alcazar and their friends in one go. However they evaded the attempt and fled into the jungle.
Frustrated by this set-back, Sponsz told Alvarez to find the fugitives and to exterminate them with napalm, bombs and rockets. His orders do not appear to have been carried out since Tapioca himself was quite content with parachuting crates of whisky into the area and making Alcazar's men too drunk to be able to carry out a coup. However, Calculus had invented some tablets which put people off alcohol and gave them to the drunken rebels, thus proving yet again a thorn in Sponsz's side.
During the carnival, Sponsz stood on the balcony of the Presidential Palace with Tapioca. Alcazar and his rebels, disguised in carnival costumes, seized control of the Palace as part of a coup and forced Tapioca to surrender power. Until this moment, Tintin and Haddock had never confronted Sponsz face-to-face, so they took advantage of the situation in order to finally look him in the eye and show that they had beaten him once again.
As Tintin had forced Alcazar to agree to a bloodless revolution, Sponsz was not executed by the new government of San Theodoros. Instead, Tintin arranged for him to be flown back to Borduria the following day. Although Tintin spared his life (or perhaps because of it), Sponsz appeared dismayed at the prospect of returning home.
In the course of illustrating Tintin and the Picaros, Hergé found that he had gone beyond the 62-page limit required by his publishers. He therefore took out a page featuring Sponsz and his aide Colonel Alvarez.
In this deleted scene, Sponsz drinks some alcohol after telling Alvarez about how it was he who framed Tintin and his friends as part of his revenge. He then excitedly announces: "I will break them, like... Like breaking this glass!" He throws the glass to the floor, but it is unbreakable, and bounces back, breaking the moustache of a bust of Kurvi-Tasch! Colonel Alvarez bursts into laughter, before being put in his place. Sponsz suspects that Alvarez will claim that he broke the bust deliberately. He thus warns the young officer about his prospects for advancement, before telling him to "sack that clumsy cleaning lady who broke Kurvi-Tasch's moustache". This incident demonstrates a paranoid aspect of Sponsz's nature, showing him to be somewhat insecure despite his political power, and unwilling to take chances in a dictatorship, picking suitable scapegoats for his own mistakes.