With centrist French presidential candidate Emmanuel Macron topping the polls in Sunday's first round of voting, many are heralding the political upstart's ability to overturn mainstream politics. But one Goldman Sachs economist sought to calm the fever surrounding Macron, also placing him within a broader European political movement.

Macron's leading 23.9 percent of the vote represents "quite a fundamental realignment of politics in France, and maybe more broadly in Europe," Huw Pill, chief European economist at Goldman Sachs, told CNBC's Squawk Box Monday. But, he detailed that "perhaps we should interpret this as a very important step, but still only a step."

For Pill, France's runoff vote on May 7 reflects a broader trend in which: "The traditional left/right spectrum of political opinion maybe is dissolving, or at least is being paralleled with another spectrum going from the sort of Eurosceptic, more nationalistic side, towards a more internationalist, pro-European globalist side." This was also reflected in March's Dutch election, which saw incumbent pro-Europe Prime Minister Mark Rutte retain his position.

Pill also chimed in with others arguing that Macron must win big in June's legislative elections in order to most smoothly implement his reformist agenda. The En Marche! candidate "needs to build a new coalition," he explained.