A video showing the attack was widely shared on social media on Tuesday
Lebanese security forces detained on Wednesday a group of men who physically and verbally assaulted a Syrian refugee.
A video showing the attack - widely shared on social media on Tuesday - prompted a public outcry.
During the beating, the men are heard shouting expletives at a refugee named Uklah and asking him if he had planned to take part in a protest the following day.
The men demanded of Uklah that he praise the Lebanese army and president and curse the Islamic State and the Syrian people.
Uklah is identified as a native of Deir Ezzor, an eastern province in Syria, mostly under IS control.
The men are also shown kicking Uklah all over his body as he lies on the ground, begging them to stop.
A voice note calling on Lebanese to "beat Syrians" was shared on WhatsApp, according to journalist and blogger Kareem Chehayeb.
The attack occurred ahead of a protest in solidarity with Syrian refugees planned for 18 July but which was cancelled due to threats.
Tension has heightened around Syrian refugees in Lebanon, who account for an estimated one in four people in the country.
The Lebanese president has said that the country "can no longer carry the burden" of refugees while denouncing "hate and incitement".
Four Syrians died in custody after being tortured by Lebanese soldiers following army raids on refugee camps in Arsal, in the country's east. A four-year-old girl was killed in the raid, although the army claimed she died in a suicide attack.
The possibility of death under torture in Lebanese army custody came against a background of previous accounts of abuse by security services.
Last December, Human Rights Watch (HRW) published the harrowing account of a Syrian refugee who said he was beaten, verbally abused and had a rod pushed up his anus at Rehanieh military police prison on the suspicion of being gay.
HRW has thoroughly documented 10 cases in which civilians in Lebanese military detention said that they were tortured. This included during interrogations, when none of them had access to a lawyer or their families.