Built in the 13th century at rue de Tambour, adjacent to Hôtel des Comtes de Champagne, Maison des Musiciens was a beautiful Gothic mansion. It was celebrated for the five façade sculptures of musicians, each placed in a separate Gothic niche. Unfortunately, the mansion was completely destroyed in WWI bombings, but the statues miraculously survived. They were salvaged and moved to a museum (Musée Saint-Rémi, see separate tip) where the façade was reconstructed, as seen in the attached photo. The second photo shows how the palace looked before it was destroyed.
Taken at Musée Saint-Rémi, this photo is of a sketch of what a historian believes the Roman Triumphal Arch (Porte Mars) might have looked like upon completion in the 3rd century AD. Only the lower level, with its triple arches and faded decorations, has survived. The entire upper level and the bronze statues above it have disappeared.
Listed as a UNESCO World Heritage Site together with the adjacent Basilica, this complex was once the Abbey of Saint-Rémi, where the Holy Ampulla, used for the coronations of French kings, was held. It is nowadays a museum of the art, architecture and archaeology of Reims from pre-historic times to the Renaissance period. Although the Abbey of Saint-Rémi was founded in the late 8th century AD, most of it was reconstructed in 17th and 18th centuries. Its front courtyard (Cour d'Honneur) opens onto a palatial Louis XVI-style edifice, completed in 1709 along with the cloister behind it, by the architect Jean Bonhomme. The cloister leads into le Parloir and la Salle Capitulaire, the oldest surviving halls which boast 13th century Gothic ceilings supported by 12th century Romanesque column capitals. From le Parloir, the refectory and kitchen are accessed, which display a rich collection of Gallo-Roman artefacts from the days of Durocortorum, i.e. Roman Reims. Other notable features include l'Escalier d'Honneur, a grand stairway completed in 1778, and la Salle des Tapisseries, where ten large Renaissance-period tapestries detail the life of Saint Rémi. Also interesting is la Salle Gothique, which displays vestiges of mediaeval Reims including the non-extant Maison des Musiciens (see separate tip).
For more photos, take a look at the travelogue: "Musée-Abbaye Saint-Rémi."