Do digital technologies affect the breadth of cultural taste? Digital sociologists have warned of "filter bubbles," and of persisting digital inequalities; cultural sociologists have shown that cultural diversity is valued and serves as a marker of upper-middle-class status; but there are few empirical studies of the link between the two, and all are correlational. We estimate the effect of using streaming platforms on the diversity of cultural consumption using survey data from France(Pratiques culturelles 2018, n = 8692). We apply template matching to adjust for six sets of confounders, demographics, social position and origin, cultural participation during childhood, intensity of cultural consumption, the overall propensity towards diversity, and digital uses. We find a significant, positive effect of using streaming platforms on the diversity of cultural consumption, measured by the number of cultural genres declared to be consumed, across three domains, music, movies, and TV series, as well as on the propensity to watch movies and TV series in a foreign language. The magnitude of this effect is relatively low for music(.1 sd, .2 genres), intermediate for movies(.2 sd, .6 genres), but high for TV series (.46 sd, 1.2 genres). The study brings new evidence against the filter bubble thesis; it shows that platforms do reinforce cultural inequalities by increasing the gap in cultural diversity between the working classes and the elite; and it suggests that the effect of technology on cultural consumption might be mediated through its impact on cultural markets rather than changes in cultural experience.