This is a summary of an article from Polish media with additional information from reliable sources that were present at the march.
The link is here
The article estimates 50,000 people, but one photographer known to the translator estimated the actual turn out at closer to 200,000 people.
In the video at the source link, from the 100,000-strong Independence March** on 11 November, the chant is “Two brothers – a Pole and a Hungarian”.
(this phrase alludes to a saying (in Polish): “Polak, Wegier – dwa bratanki. Do szabli i do szklanki”. In English: “A Pole and a Hungarian – two brothers. To the sword and to the glass.” )

Today friendship, an alliance in the future
Thank you Green Infidel for the translation and advice on this one.
While this content doesn’t specifically show Islam as the issue, this apparently was the point of the march. Against the migration etc. Waiting for more on this.