The Polish opposition is troubled by a new 'Russian influence law'. What is it really about?

"Poland is here!" opposition leader Donald Tusk shouted in front of a crowd of thousands of protesters gathered in central Warsaw on Sunday. "No one will silence us!"

Opposition parties and their supporters, including civil society organisations, marched through the Polish capital to mark the 34th anniversary of the first democratic elections held in Poland in 1989 since the communist party abandoned its monopoly on power.

"There are thousands of us, thousands of people with Poland in our hearts, millions of Polish women and men in front of TV sets who did not let themselves be broken, did not let themselves be intimidated," continued Tusk.

Tusk was flanked by Lech Wałęsa, a former Polish president and renowned protest leader from Gdańsk who founded the Solidarność or Solidarity movement, often single-handedly credited for ending communist rule in Poland.

The subway in the capital was jam-packed as participants made their way to the march, which began on Plac Na Rozdrożu.

While the main demands of the protesters are "free and fair elections" and a "democratic, European Poland", the march has brought together a diverse crowd of people affected by the decisions of the ruling Law and Justice party (PiS), including women's rights groups and LGBT activists.

The protests come on the heels of a bill passed last week in the Polish Sejm and approved by President Andrzej Duda that will form a commission to investigate alleged Russian influence and collaboration with Russian authorities starting in 2007.

PiS, which is the largest party in the Sejm, sponsored the bill, and is aligned with Duda.

The commission, in its currently proposed form, will investigate Russian influence on the internal security of Poland, including public figures as