Nikolai Polozov made the comments on August 9 as he wrapped up the defense case in the trial of Ahtem Chiygoz, who is charged with organizing an illegal demonstration against impending Russian rule over the Ukrainian peninsula in February 2014, RFE/RL reported.
A recording of the lawyer's remarks was posted on Facebook by a Crimean Tatar activist, Nariman Dzhelalov.
Polozov compared Russia's annexation of Crimea with the annexation of Austria by Adolf Hitler's Germany in 1938, saying that in both cases officials used slogans about "the unity of the nation, historic justice, and return to the native harbor."
He also said in Austria and in Crimea, opponents of the takeover faced reprisals.
"Those Austrians who wanted to see their country independent were tried and sent to concentration camps, similar to what Russia is doing now with those who oppose the annexation," Polozov said.
Rights groups and Kremlin critics say that the trial of Chiygoz is part of a campaign of abuses and politically motivated prosecutions of Crimeans who opposed the Russian takeover.
Polozov cited a prosecutor at the Nuremberg trials of Nazi leaders after World War II as saying that they were "the first case when criminals who seized a country to commit their horrendous crimes were brought to a courtroom."
"Unfortunately, in my country, in the Russian Federation, what we see in the last 18 years is the same: criminals who seized the country and are using it for their horrendous crimes," Polozov said.
Putin has been in power as president or prime minister since 1999.
Polozov said that after "suppressing freedom of speech and political competition" at home, "Russia's current leadership decided to do the same in the neighboring countries."
He urged the judge and court officers "not to become accomplices of those who seized this country and not to do evil things along with them."
"I call on the court to make a moral choice.... because in 1938, when Austria was seized, nobody thought that in seven years, many of the functionaries and their flunkies ended up...in courtrooms as defendants, at the least," he said.
Polozov's statement came two days after prosecutors asked the court to convict Chiygoz and sentence him to eight years in prison.
Defense lawyers say the charge against Chiygoz is absurd because the demonstration against Russian moves to seize control of Crimea came before Moscow took control of the peninsula the following month, and no Ukrainian laws were violated.
Russia has been sharply criticized by international rights groups and Western governments for its treatment of members of the indigenous Turkic-speaking Crimean Tatar minority.
Read alsoOccupied Crimea's "prosecutor's office" requests 8 years in prison for activist ChiygozChiygoz, 52, is a leader of the Mejlis, the Crimean Tatar assembly that was outlawed by Russia after Moscow's forcible takeover of the Black Sea peninsula.
Two other Crimean Tatars charged in connection with the demonstration – Ali Asanov and Mustafa Degermendzhy – are recognized as political prisoners by the Russian human rights group Memorial.
The Parliamentary Assembly of the Council of Europe (PACE), the Organization for Security and Cooperation in Europe (OSCE), and other international organizations have called for their release.
Russia moved swiftly to take over Crimea after Moscow-friendly Ukrainian President Viktor Yanukovych was driven from power by pro-European protesters in February 2014.
Russia seized the peninsula, which is home to a major Russian naval base, by sending in troops and staging a referendum dismissed as illegal by Ukraine, the United States, and a total of 100 countries.
The Russian takeover badly damaged Moscow's relations with Kyiv and the West and resulted in the imposition of sanctions by the European Union, the United States, and several other countries.