France fears a repeat of its disastrous falling-out with Mali in junta-ruled Burkina Faso, where another domino in its military cooperation against West African jihadists could topple.
French troops withdrew from Mali last year, after a 2020 coup in the former French colony saw its rulers inch closer to Russia.
Burkina Faso, also once under French rule, now seems to be moving down the same path, after officers seized power there in September, in the second coup in eight months.
France has 400 special forces stationed in the country to battle a jihadist insurgency.
But relations have deteriorated in recent months, and Burkinabe Prime Minister Apollinaire Kyelem de Tembela in November said he hoped to "diversify partnership relations" in the fight against jihadists.
"Russia is a reasonable choice," Tembela said on Saturday after meeting Russian ambassador Alexey Saltykov.
The premier also made a discreet visit to Moscow in early December.
In Mali, France fell out of favour with the junta after the alleged arrival in 2021 of operatives from the murky Wagner Russian mercenary outfit to bolster government forces.
Behind the scenes, the Burkinabe military government has sought to reassure Paris that it does not intend to enlist Wagner's help.
But French sources say a delegation from the mercenary group has visited the mineral-rich country, where a Russian firm already operates several gold mines.
French special forces are staying in Burkina Faso for now, but could leave immediately if President Ibrahim Traore strikes a deal with Wagner.
Their preferred scenario would be to redeploy to neighbouring Niger, where 2,000 French troops are already stationed, two sources familiar with the plans told AFP.
Some experts say this scenario is becoming unavoidable, as the former colonial power has not managed to help quell the jihadist violence wracking the impoverished country since 2015.
"The Sahel is undergoing a deep transformation, one of increasingly strong anti-French sentiment," said Alain Antil, an expert on the region at the French Institute of International Relations.
Resentment is felt not just among "certain elites" but also shapes "public opinion in big cities", he said.
Paris may allege "this Francophobia is entirely fabricated by geopolitical enemies", Antil added, but it in fact runs "far deeper".
African governments need to take this into account, the researcher said, and the French military presence in the Sahel would "likely" be drastically reduced eventually.
In October, anti-French demonstrators gathered outside France's embassy in Ouagadougou and the French cultural centre was attacked.
Another demonstration outside the embassy followed the next month.
In early January, the French foreign ministry said it had received a letter from the junta asking for ambassador Luc Hallade to be replaced after he ruffled feathers with reports on the country's worsening security situation.
The tensions were such that Paris dispatched deputy foreign minister Chrysoula Zacharopoulou to meet Burkina's president.
"I didn't come here to influence any choice or decision. No-one can dictate Burkina's choices," she said after meeting Traore.
Clear about consequences
A diplomatic source said the visit did not intend to force the African country to choose sides but Zacharopoulou "was very clear about the consequences of the choice the authorities would make".
Burkinabe analyst Drissa Traore said tensions were still the same, even after the visit.
"The transition authorities are determined to form new partnerships, or even revitalise them, with Russia in pole position," he said.
French President Emmanuel Macron has given himself until spring to rethink military partnerships in Africa, which are to be less visible and more closely aligned with the specific demands of host countries.
Draw first conclusions
He should draw the first conclusions "in the coming weeks", a government source said.
France does not want to lose strategic ground in a continent set to be home to 2.5 billion people by 2050.
But Antil said it was also in France and its partners' interest to avoid any jihadist violence spilling over into North Africa.
"While it's not in its closest vicinity, the Sahel is still part of Europe's southern neighbourhood," he said.