Rouissi says much of Casablanca was built as an experiment in early 20th century urban planning and today there are about 4,000 buildings in need of help.

Real-estate developers often look to buy historic properties, tear them down and build more modern apartment buildings through which they can charge higher rents and recoup expenses.

Part of the problem, Rouissi said, is that tenants in existing apartment buildings pay very low, fixed rents and landlords are only able to remove tenants if they pay a hefty relocation cost of about 50,000 euros ($66,000).

Developers have been known to have a cosy relationship with local officials and building demolitions are sometimes rubber-stamped.

“Rebuilding is done at the expense of the city and its heritage,” said Rouissi, whose association is hoping Casablanca will be ranked as a Unesco (UN Educational, Scientific and Cultural Organization) World Heritage Site.

Though local authorities have been slow to act in the past and there is no national strategy to preserve architectural heritage, they are becoming more responsive to preservationist pleas, Rouissi said.

Some of the city's rapid redevelopment can be seen along the Boulevard Mohamed V, one of the city's oldest roads. Today, much of the street has become a construction site for a future tram line, though architecture buffs still flock to the area to look at old buildings.

In the historic town centre, a short distance from the ancient medina, or old Arab quarter, the famous Excelsior Hotel has become one of the hippest cafes in Casablanca, a diverse city of about five million residents and the beating heart of Morocco's economy.

The Excelsior is adorned with a whitewashed colonial facade, built by French architect Hippolyte-Joseph Delaporte in 1916 and decorated with Spanish tile.

Across the road is the main entrance to the medina, the ancient city where Jews, Muslims and Christians co-existed for years, where an old Catholic church is today being converted into a cultural centre.