Authorities rounded up a total of 11 Turkish and German suspects in the southern state of Baden-Württemberg and in North Rhine-Westphalia in western Germany, the German federal police bureau in Stuttgart said.
Turkish authorities detained another 33 suspects in the Istanbul region in February as part of the same operation, codenamed "Akku" (battery), the bureau said in a statement.
The ring, based in Turkey, operated primarily from Istanbul using trucks with hollowed-out storage spaces in which up to 113 people could hide, police said in a statement.
"Those being smuggled faced significant risks to their health and lives depending on high temperatures and the materials used to cover them in the hold," the statement said.
The trucks travelled from Istanbul via Athens by ferry to Italy, from where the illegal immigrants fanned out to other EU member states. The groups also used two yachts and chartered ships to spirit people into Italy.
"This case makes clear that organised crime is also very active in this area and has increasingly specialised in breaching the borders of the Schengen (passport-free) zone," the bureau said.
"The close cooperation of the (German) federal and state police with Turkish authorities as well as other European police bureaus was the key to the investigation's success."