The scandal was not over an inebriated officer behind the wheel at 1am - such an everyday occurrence won't cause much of a stir in this cynical capital. But irreparable damage to a 14th-century Aztec stucco stairway and ugly oil stains caused considerable breast-beating.
Eduardo Matos Moctezuma, who directs the museum on the temple site, was dumbfounded when a magistrate freed the policeman on bail after just seven days. "This is imprudent," he said. "We cannot permit a gentleman in these conditions, who ought to be taking care of us, to destroy the patrimony in such an outrageous way."
The accidental rediscovery of the Templo Mayor was relatively recent - electrical workers laying cable for an underground system in 1978 came across twin altars to the rain god and war god and put their pickaxes aside to gape at a mural of eagle warriors and their victims' skulls.
Eventually, the metro was rerouted and archaeologists uncovered some seven thousand relics spread among 110 altars. Although the most famous treasures, such as the massive calendar stone, are displayed some miles away at the National Museum of Anthropology, curious visitors come by the thousands to see the original site.
A great turquoise disc, inlaid with 15,000 mosaic pieces that forms a circle of seven linked warriors, was unveiled for the first time on Friday after a five-year restoration programme. Ordinary citizens take immense pride in the glories of pre- conquest Mexico. The ruins of enormous cities built by the Aztecs, Mayas, Toltecs and Olmecs are a testament to civilisations that pre-dated the arrival of the Spanish. Many Mexicans were rather annoyed at recent archaeological discoveries in Mayapan that punctured one long-held belief. Analysis of bone fragments this summer revealed that the Mayans had suffered from syphilis at least a century before the conquistadores arrived.
Although the Spaniards stole the foundation stones of the city's cathedral from the Tenochtitlan temple more than 400 years ago, most Mexicans hold both structures in equal regard.
Ancient symbols are stillemblematic of popular Mexican culture: the skull motif, the murals and bold graffiti, even the strident colours once painted over the Aztec and Maya structures. Modern Mexican builders often daub magenta next to brilliant yellow, while others are partial to an intense ultra-indigo that seems to shimmer in the sunlight. The pyramids were once just as garish.
Elsewhere few politicians would attempt a $13m re-make of a museum in an election year of a country so steeped in economic turmoil. But President Ernesto Zedillo is intent on refashioning the National Museum of Anthropology into a state-of-the art showpiece, for completion in December 2000 - just as he leaves office.
But in Mexico, where locals typically outnumber foreign tourists in the museum, any criticism of the project - for instance suggesting that it is wrong-headed when the descendants of the honoured tribes go hungry in the provinces - is muted.