But it was not that many years ago that the same protestors, or their older brothers and fathers, were shooting at each other during Lebanon's 15-year civil war.
Christian opposition leaders say it has taken years for their community to begin to feel at ease with their Moslem neighbors since the civil war ended in 1990. They say that the extent to which the opposition members mix today is largely due to reconciliation efforts. Those efforts have been both with the Moslem community and between various factions in the Christian community itself.
Samir Franjieh is a prominent Christian opposition leader with years of close ties to the Moslem community in Lebanon. He says the first major reconciliation effort came from Pope John Paul II in 1997.
He says that the Roman Catholic leader urged Christians in Lebanon to put aside their differences and recognize that they and the Moslems both share the blame for the country's bloodshed. The effort took four years of hard work before it began to bear fruit. "During these four years, a big evolution occurred inside the community, inside the Christian community," Franjieh said. "People began to consider that we cannot live alone without the Moslems, came to know that we cannot speak of our differences without giving recognition to the difference of the other community."
The next big breakthrough in the Moslem-Christian relations came in 2001 when the Christians signed a peace treaty with Druze leader Walid Jumblatt. The Druze sect is an offshoot of Islam.
Jibran Tueini is the publisher of the An-Nahar newspaper and hails from an influential Christian family. He says the treaty with Jumblatt -- who today is a key leader of the opposition movement against Syria -- had wide ranging political significance. "This brought the mountain, and Beirut, and Mount Lebanon (eds: different regions of Lebanon) together," Tueini said. "And this, for us, was very important, crucial, because as long as the mountain was divided, meaning the Druze and the Christians, Lebanon was very weak. And it is known through history that when the mountain is unified, the Druze and the Christians, Lebanon is very strong. It is the backbone of Lebanon."
But the reconciliation efforts are still far from complete, as political splits -- even within families -- can show.
The politically prominent Lahoud family, which is Christian, is one example.
Lebanese President Emile Lahoud is staunchly pro-Syrian. But a close relative, Nassib Lahoud, is a prominent figure in the opposition movement.
There are similar splits in the equally prominent Franjieh family. There, Samir Franjieh is an active member in the opposition movement. But his cousin, Suleiman, is interior minister in the resigned cabinet of Omar Karami and is solidly pro-Syria.
Many analysts warn that as the crisis in Lebanon heats up over demands for Syria to pull out its troops, the political divides could deepen. That raises fears that the still fragile reconciliation process could be challenged by passions that already have proved strong enough to plunge Lebanon into civil strife.
In a sign of the mounting tensions over Syria, Christian leaders in Lebanon regularly dismiss people like the president by saying they are Syrian tools with little domestic following.
But the government's supporters -- including the powerful Lebanese Shi'a Hizballah party, accuse the opposition parties of equally being agents of outside powers.
Hizballah leader Sheikh Hassan Nasrallah has charged unnamed Christian leaders with wanting to bring Israel back into Lebanese politics. During Lebanon's civil war, several Christian factions had close ties to Israel and received money, arms and training from the Jewish state.
The challenge for the opposition parties seeking to expel Syria is now to become an independence movement that can transcend such differences.
Former President Amin Gemayel, a Christian, is one of the opposition figures seeking to do that. He maintains that many of the opposition slogans shouted these days in Beirut's Martyrs Square were originally mottos of the Christian community.
He says that today those mottos belong to all Lebanese seeking to assert their national identity. "Don't forget that in the beginning those slogans you hear actually were our slogans first," Gemayel said. "Since the year 2000, we used to launch those slogans of sovereignty and Syrian withdrawal. And many others have joined the process, (particularly) some Moslem leaders (who have) decided to join this movement toward the independence of the country."
Christian opposition leaders say the joint Christian-Moslem protest against Syrian control has now reached a level that they are no longer afraid Syria can crackdown on the anti-Syrian factions.
As one opposition leader put it, "the Genie is out of the bottle and they cannot put us back in the cage."
Only time will tell if that prediction is correct.