Days later, euro zone reforms, defense cooperation and immigration will be in focus when Macron hosts the leaders of Germany, Spain and Italy for talks, as he tries to enhance France's leadership in Europe.
Paris has long complained that central and eastern Europe gains an unfair advantage from the "social dumping" of cheap labor, arguing the posting of low-paid workers hurts local jobs and erodes labor protections in higher-wage member states.
Although posted workers make up less than 1 percent of the EU workforce, with many employed in the haulage and construction sectors, the issue has deepened a divide between the poor east and rich west.
Macron will visit Romania, Bulgaria and Austria, where he will also meet the leaders of the Czech Republic and Slovakia, but is skipping Hungary and Poland, whose right-wing governments he has accused of spurning the bloc's values.
An Elysee Palace source said Macron was visiting countries who were "the most attached to their European anchoring".
A senior French diplomat said the president was deliberately snubbing Poland and Hungary "to send a message to Warsaw and Budapest".
Macron's election win has re-energized the EU's Franco-German axis but in central and eastern Europe it has fanned fears of a "multi-speed" Europe that could mean reduced influence, financial support and economic competitiveness.
The diplomat said Macron wanted to reassure the leaders he meets that the future of their countries would remain at the heart of the European project if they fall in line with the broad reform agenda led by Paris and Berlin.
Macron will find a sympathetic ear in Austria, which borders four central European countries and where the ruling Social Democrats say an influx of workers from the east is weighing on wages.
The posted workers directive permits European companies to send employees to other EU states on contracts under which they have to guarantee only the minimum wage of the host country.
Macron has said a European Commission proposal that posted workers' pay packets should include benefits in line with host country regulations and that their contracts be limited to two years does not go far enough.
Poland, Hungary, Slovakia and the Czech Republic -- known together as the Visegrad four -- say the proposals go too far. They argue they should be allowed to compete on lower prices to catch up after decades of communist stagnation.
Estonia, which holds, the EU's rotating presidency, is due to table a new proposal in September.
Poland has accused Macron of double standards by advocating a closer Europe while seeking to erode competition in the single market. Two sources in the Polish government said it had tried to invite Macron to Warsaw as part of his trip.
"But we didn't see much willingness," said one of the sources.
Poland's Deputy Infrastructure Minister Justyna Skrzydlo told Reuters the Warsaw government trusted in the "continued unity and solidarity of the Central Europe countries".
Other countries have shown signs of being open to compromise and aligning themselves with an eventual new EU proposal.
"I am very much interested in regional cooperation within the Visegrad four, but Slovakia's vital interest is the EU," said Slovak Prime Minister Robert Fico.
A senior Czech official said his government could move closer to the French position if it won assurances on the migrant crisis. A number of central and eastern European governments are resisting an EU scheme under which member states should accept asylum seekers from countries such as Syria according to a quota system.
"We do not see quotas as an effective solution to the crisis. We would welcome hearing alternative measures as the focus for dealing with migrants. That would be enough for the Czechs and would unblock discussions in other areas," the official said.
Beyond the issue of posted workers, Macron is likely to be on a charm offensive to drum up support for proposed wider reforms to the European Union that include deeper defense cooperation, fiscal harmonization and a common budget for the euro zone.
His advisers say French diplomacy has long neglected central Europe.
"He wants to get started on Europe. The sooner he starts building these relationships, the more political capital he will accumulate to use at a later stage," said Teneo Intelligence analyst Antonio Barroso.
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