This demonstration, in the provincial capital Goma, called for authorities to enforce a ceasefire agreed with the M23 group last year.
City authorities had banned the march.
But that didn't stop hundreds from taking part.
Police deployed tear gas to disperse the gathering.
Among protesters denouncing a regional military force set up by the East African Community to end the conflict, was Gloire Bagaya.
"We don't want them to be here as tourists. They should either go home or go to the front line against the enemy. They are even doing selfies with members of the M23, we don't want them here anymore."
The M23 has been accused of flouting the deal agreed with regional leaders in November.
Critics allege it has occupied territory elsewhere to compensate for withdrawals that are considered to be mainly ceremonial.
Congo's President Felix Tshisekedi made similar accusations on Tuesday (January 17).
The M23 has denied the claims and in turn said it is the Congolese authorities who are breaching the agreement.
The rebels' latest offensive has sent at least 450,000 people fleeing their homes.
Congo, Western powers and United Nations experts accuse neighboring Rwanda of supporting the rebels - which Rwanda denies.
