I knew that. Toilets here contain a bewilderment of parts, and I knew that the water intake contraption leaked as well as the column that controlled both the flushing mechanism and the shutoff valve -- one of the shutoff valves. The other valve float seemed to stick a bit. Something also vibrated so loud that the neighbors may have noticed. And the flush trip mechanism didn't fit securely.
So he took all the Rube Goldberg plastic doohickeys out, put in new and what looked like more complex ones, checked his work, cleaned up nicely, and took our money (a mere 80 euros/US$105). It is now safe "to change the water in the canary cage," as they say here.