This article draws on a fieldwork conducted with registry officers in charge of tracking down fake marriages to analyse racialised social relationships in Switzerland. It shows that administrative practices play a decisive role in controlling the symbolic borders of the nation, as its reproduction modalities, organized around the ideology of whiteness. Relying on the analogy between emic expressions of mixity and binationality, the author sheds light that beyond the muteness of race, references to racialized readings of bodies — skin colour — as well as other identity markers — nationality, gender and sexuality — are crucial even when unspoken to determine the admissibility of marriage claims. Couples deviating from the implicit norm of racial homogamy are submitted to discipline and scrutiny aiming at calling them to order.